frequently asked questions

First off, make sure the correct size, (cfm) carburetor is installed on the engine and be sure the idle mixture screws are properly adjusted (see page 6 of the Owner's Manual). You can always make your carburetor leaner, but this will not always improve gas mileage. Since every engine is different, there is no way of knowing how much of an affect leaning down the carburetor will have on your engine. You can refer to your carburetor owners manual and the calibration chart inside to lean down the carb. Start off light, but keep an eye on the plugs to make sure you aren't taking it too lean. You will see on the chart that you can lean the carburetor down in different percentages in different modes, cruise and power.

There is no "pre-determined" combination of rods and jets for any given motor, accept for altitude corrective applications, which is 4% for every 3,000 ft of elevation. Every engine is going to require a different fuel curve. The best thing to do is run the carburetor on the engine right out of the box to build a baseline, then check the spark plugs and see how they look. You need to have a light brown, or tan color on the plugs. If they are too white or too black, you need to make adjustments, refer to the tuning chart in your carburetor owners manual. Plug reading gives you an accurate idea of what is actually taking place inside the combustion chamber. Please note, today's re-formulated fuels can leave a lack of accurate colorization.

Fuel in the oil can be caused by several conditions including a ruptured fuel pump diaphragm, incorrect fuel line hook-up, and carburetor flooding. If the problem is carb flooding, check the following: Fuel pressure should not exceed 6.5 psi. Float level should be verified to be at 7/16. Refer to supplied carburetor owners manual. Verify needle & seats are free of any debris, and have a smooth range of operation and travel. Verify floats are free of any fluid by shaking the float, or submersing it in a safe, non flammable fluid.

This may be caused by a rip or tear in a base gasket, air horn gasket, or adapter gasket or some foreign material stuck in an air passage of the carburetor. Inspect the gaskets to make sure you have no vacuum leaks of any kind. Check to make sure carburetor is seated correctly, and is fastened with the correct hardware. You can perform a quick check to find external vacuum leaks (such as a leaky carb base gasket) by spraying starting fluid on suspected areas while the engine is idling. If the engine speed changes for a second or two after you spray an area of the carb, you've found the leak.

Check for correct choke operation and adjustment. Make sure that the fast-idle cam is not causing this. Verify the throttle arm rests on the idle speed screw. It is important to verify throttle linkage, and or throttle blades are not binding and have a free range of operation. Throttle return spring should be correctly located and adjusted. In most cases, the return spring should be positioned on the top of the throttle arm forward. This should have been confirmed when the Wide-Open Throttle test was performed during the initial installation of the carburetor. Make sure all of the vacuum ports on the carburetor are being utilized or blocked off.

The 1406 is calibrated lean for fuel economy. In some applications, re-calibration of the carburetor may be necessary for optimum performance. See page 22-23 in the supplied carburetor owners manual. Step # 23 on the calibration reference chart is a good starting point for enriching the air/ fuel mixture.

All of Performer Series and AVS carburetors feature the PCV port on the front center of the carburetor; it can only be used for PCV. The fuel inlet is on the passenger side rear of the carburetor. Incorrect installation of the fuel line can cause severe engine damage.

The Electric choke on our Performer Series and AVS carburetors needs to be hooked to a "keyed" (while the key is in the on position) 12-volt power source, with a good ground. Verify there is no voltage when the key is in the off position. Do not connect the positive wire to the Ignition Coil, ballast resistor or Alternator.

Carburetor flooding can be cause by the following conditions. First, verify, with a fuel pressure gauge that the pressure does not exceed 6.5 psi. Floats should be set to the factory spec of 7/16, (see carburetor owners manual). Needles & Seats can be clogged with debris, not allowing them to close. They can be cleaned and checked when the float level is being verified. Floats can be sinking due to a leak. Verify floats are free of any fluid by shaking the float, or submersing it in a safe, nonflammable fluid.

Edelbrock do not recommend routing the PCV line to the rear of the carburetor. We recommend that the PCV line go to the front, if you have power brakes, they go to the rear.

Both Idle mixture screws on the front of our Performer Series and AVS carburetors control air/fuel mixture at idle. The left screw controls the left venturi and the right screw controls the right venturi. Refer to your carburetor owners manual to properly tune the idle mixture.

Generally the distributor vacuum line goes to the timed (pass side of carburetor) port. This is mandatory on emission controlled applications.

An incorrect float level can cause this to occur. Make sure that the float levels are set properly at 7/16" per the carburetor owners manual. Excessive fuel pressure can also contribute to this condition.

Too much fuel pressure usually causes this and often times dirt in the float bowls can do the same. Make sure your fuel pressure does not exceed 6.0 psi, optimum pressure is 5.5 psi.

There are many different circumstances that would cause fuel to leak out of a carburetor. Below are a few reasons why you may see a fuel leak along with some possible solutions.

• Fuel pump pressure is too high. The fuel pump pressure should be no more than 6.5 p.s.i.
• Take the top of the carburetor off and check for debris in the needle & seat, also inspect the needle tip to be sure it has not been compromised.
• While the float is off, shake the float for any signs of fuel in the float. If there is fuel in the float replace float.
• Check float level, the float level should measure 7/16”. Measure the float level by turning the carb lid upside down and placing a 7/16” drill bit between the airhorn gasket and the top of the outer end of the float just past the inboard float radius.
• With today’s fuels, another cause of leaking fuel could be heat soak. Heat soak is when the heat from the engine compartment heats up and can boil the fuel in the float bowls. When this happens, the fuel can get forced through the venturi booster and drip into your engine. This can also cause fuel leaks through the airhorn gasket.

If the choke is not opening all the way this is usually caused by either a misadjusted choke or improper voltage supply. The best time to set your choke is in the morning when the engine is cold and the outside temps are on the lower side. With no power supply to the choke hit the throttle, the choke should close and you should have about an 3/16” gap between the choke valve and the airhorn. If your choke is out of adjustment just loosen the 3 choke cap screws and rotate the black choke thermostat until you achieve a 3/16” gap (counter clockwise leaner). If you must adjust the choke be sure to hold the throttle lever open about a ¼ of the way. This will ensure that the fast-idle cam is out of the way and will not interfere with your adjustment. If the choke is adjusted properly and it still will not open fully, you may have a problem with the voltage supply to choke. The choke needs a key-on 12 volt power source. This means it is necessary to have 12 volts while engine is running and no power when the engine is off. With the wire disconnected from the choke check to be sure you have 12 volts when the key is on. If not find a new power source. Do not connect the positive wire to the Ignition Coil, ballast resistor or Alternator.

There are many reasons why your idle mixture screws do not affect the engines idle, this is usually caused from a flooding condition. Below are a few circumstances that may cause your idle mixture screws to not function properly along with some possible solutions.

• Be sure you have no vacuum on the timed port on the front of the carburetor (passenger side vacuum port). If you have vacuum on this port then the throttle blades are open to much. This will cause the idle mixture screws not to function as you are now pretty much out of the idle circuit and the primaries are feeding the engine with fuel. To correct this the throttle blades must be closed more, so you will need to adjust your idle speed screw until there is no vacuum on the timed port. If your engine is now idling to low in some cases you can advance your timing to bring engine speed back up. Also for non-emissions use you can run your distributor vacuum advance to the full vacuum port on the driver’s side front of the carburetor.
• Fuel pump pressure is too high. The fuel pump pressure should be no more than 6.5 p.s.i.
• Take the top of the carburetor off and check for debris in the needle & seat, also inspect the needle tip to be sure it’s not compromised.
• Take the carburetor lid off and remove the floats. Shake the float for any signs of fuel in the float. If there is fuel in the float replace float.
• Check float level, the float level should measure 7/16”. Measure the float level by removing the lid and turning lid upside down. Then place a 7/16” drill bit between the airhorn gasket and the top of the outer end of the float just past the inboard float radius.

The top hole closest to the pivot point will give you the biggest pump shot of fuel. The bottom hole furthest away from the pivot point will give you a smaller pump shot of fuel. Making these adjustments can be a great way to fine tune your off idle performance.

At an idle you should never see any moving fuel at all. The fuel delivered to the engine at an idle is delivered below the primary throttle blades so you can’t see the fuel at an idle. If you are seeing any fuel at an idle then you are dealing with a flooding condition. Below are the things to check to resolve a flooding condition.

• Fuel pump pressure is too high. The fuel pump pressure should never exceed 6.5 p.s.i.
• Take the top of the carburetor off and check for debris in the needle & seat, also inspect the needle tip to be sure it’s not compromised.
• Take the carburetor lid off and remove the floats. Check the float for any signs of fuel in the float. If there is fuel in the float replace float.
• Check float level, the float level should measure 7/16”. Measure the float level by removing the lid and turning lid upside down. Then place a 7/16” drill bit between the airhorn gasket and the top of the outer end of the float just past the inboard float radius.

A ticking sound from the carburetor would be caused by the metering rod step-up piston assembly hitting the metering rod over plates. The only way this would happen normally is due to the engines vacuum being at or near the same as the rating of the step-up spring. To correct this a lighter step-up spring would need to be installed. As a base line, you want the step-up spring vacuum rating to be half of what your engines vacuum is at an idle for best performance.

The Performer/Thunder series carburetors do not need to be removed from the intake manifold to do jet and rod changes. Just use caution and not drop any parts down the throttle bores. Metering Rod and Step-Up Spring changes can typically be made in less than five minutes and without removing the carburetor. First, loosen the Step-Up Piston Cover Screws and twist the Step-Up Piston Cover Plates to the side. The Metering Rods and Step-Up Springs can now be removed and replaced if necessary. Be sure to replace the Step-Up Piston Cover Plate and snug the Step-Up Piston Cover Screw when finished. CAUTION: Do not overtighten the Step-Up Piston Cover Screws! They should only be tightened to 12 to 17 inch/pounds. Excessive torque will weaken or snap off the screw heads. If this happens, they may fall into the carb causing serious engine damage. If an inch/pound torque wrench is not available, snug the screw until it just touches the plate, then tighten 1/16th turn more.

To replace the Primary or Secondary Metering Jets, first, remove the Metering Rods and Step-Up Springs as outlined in the preceding paragraph. Next, disconnect the fast idle Cam Connector Rod, Accelerator Pump Connector Rod, and Electric Choke Connector Rod (when applicable). Finally, remove the 8 Airhorn Attaching Screws (early models have 9 screws) and remove the Airhorn from the carburetor body. A standard screwdriver can now be used to remove the appropriate Metering Jets. Once desired Metering Jets have been installed the carb may be reassembled by reversing this procedure.

The Step-Up function, which moves the Metering Rod to the Power Mode, is controlled by the Step-Up Spring. The base calibration has a spring which “stages” rich at 5" Hg. If your vehicle has a mid-throttle driveability problem that is encountered as the throttle is gradually opened, but then goes away upon further opening, it may be possible to eliminate the lean spot by using a stronger Step-Up Spring. It is best to select a new spring based on vacuum readings, but in the absence of a gauge, try the strongest spring (highest vacuum rating) to see if the problem goes away. If the drive problem is cured by the strong spring, try the next weakest spring as well. If the strong one does not help, then the calibration problem is related to the A/F metering stage of either the Cruise or Power Modes. As a general rule for best performance run a step-up spring that is rated at half of what the engines vacuum is at an idle.

The Edelbrock Performer Series/Thunder Series carburetors have conventional Idle Mixture Screws (IMS) that provide a leaner A/F when turned clockwise and richer A/F when turned counter clockwise.The idle air flow is controlled by a conventional idle speed screw that opens the Primary Throttles. The following procedure should be used to set the idle mixture and speeds.

• Fully warm engine and ensure choke is fully open.
• Air cleaner in place.
• Set desired speed with the idle speed screw.
• Adjust the IMS on ONE side to get the maximum possible RPM.
• Do not go rich beyond the maximum speed point.
• If the above changed the idle speed more than 40 RPM, then re-adjust the speed.
• Adjust the side OPPOSITE of that in Step 4 to get maximum RPM.
• Reset the speed.
• Carefully trim each IMS to again get the maximum idle RPM.
• Go leaner just enough to get a 20 RPM drop in speed.
• Reset the speed via the idle speed screw to the desired RPM.
• This is a Lean-Best Idle Set. Setting richer than this will not
• Improve idle quality or performance, but could tend to foul plugs.

Another way to adjust the idle mixture screws would be with a vacuum gauge. With your idle RPM set hook up your vacuum gauge to a full manifold vacuum port. Next adjust the idle mixture screws one at a time until you get the highest and steadiest vacuum. If your idle speed is now off reset idle speed via the idle speed screw and re-adjust mixture screws until you get the highest vacuum.

There is no requirement to run a fuse for the electric choke on the Edelbrock Performer/Thunder series carburetors as the choke has a very low amp draw (.5amp). If you would feel more comfortable running a fuse you can use a 10-amp fuse for the choke power wire.

For a first step, you can pull out the carburetor idle mixture screws and blow some compressed air into the idle mixture screw holes. This can be a temporary fix since you’re just blowing the debris right back into the carburetor. To fully clean out the idle circuit you will need to remove the carburetor from the intake manifold, then remove the top of the carburetor and remove the primary venturi boosters. Clean out all the passages on the venturi booster especially the small idle jet, this is where the fuel travels through to feed the idle circuit. Take out your idle mixture screws and clean out that passage, you should have free flow from the mixture screw hole up to the passage where the venturi booster mounts.

In most cases the airhorn gasket can be reused, just inspect for any tares in the gasket before re-installation. When removing the airhorn be sure the gasket comes up with the airhorn. If the gasket is sticking to the base slide a thin flat object such as a gasket scraper between the gasket and the base to break the gasket free.

To help eliminate heat soak problems your best bet is to use a heat insulating spacer under the carb base. A heat insulating spacer material plays a huge role in insulating the carburetor for heat. The best spacer material to use is either wood fiber, phenolic plastic or one made of gasket material. Its best to run a spacer with a 4-hole design, this will help shield more heat from the carburetor. Some other tips for heat soak, be sure the fuel line is routed away from any hot heat sources like intake, exhaust and so on. You can also verify that the float levels are correct, if the floats level is too high this can compound the problem. Be sure you don’t have restrictions in the exhaust, some vehicles have heat risers in the exhaust and if they get stuck in the closed position this will cause more exhaust crossover heat under the carb.

Edelbrock does not recommend the use of an open adaptor on a stock intake manifold for a few reasons. With an open adaptor on a stock intake manifold, you can run into several problems. Installing an open carb spacer on a stock intake manifold will likely result in uneven air/fuel distribution due to the open space. With a lot of stock intakes, they have 4 holes and with an open adaptor you will have a lot of positive steps in your air/fuel charge, plus fuel will puddle on the intake carb pad. You will also lose throttle response when using an open adaptor. The only time open adaptors should be used is on single plane intake manifolds.

The main reason an accelerator pump shaft would break on an Edelbrock Performer/Thunder series carb, is that the accelerator pump connector link has been installed backwards. When you’re looking at the front of the carburetor the accelerator pump connector should look like the shape of the letter S. If your pump connector looks more like the letter Z then the connector is on backwards. If the connector is correct then check the bore of the accelerator pump well for any damage. Also, be sure that the accelerator pump passage to the nozzle is free and clear. If the passage is plugged it can cause a hydraulic effect and break the pump shaft.

If your engine is hard to start cold please know that is not normal and there are a few items to check. The first step is to be sure you’re getting a pump shot of fuel out of the accelerator pump nozzle. If the vehicle has not been running in a few days, you could be having a problem with today’s fuels evaporating out of the float bowls. If the vehicle is ran every day and you’re not getting a pump shot of fuel you may need to rebuild the carb or at least change the accelerator pump. If your accelerator pump is working properly, you will now need to see if your choke adjustment is off as this could also be the cause. Be sure when the choke is set that there is about an 3/16” gap between the choke blade and the airhorn. If the choke is closed all the way or if you have to big of a gap the engine will be hard to start cold. If the choke needs to be adjusted.

In a past FAQ we talked about how to lean your carburetor out for better fuel economy, this time I would like to give some other tips that can help improve fuel mileage. Adding a 1 inch 4-hole spacer can help improve signal to the carburetor which will help atomize the fuel better and can increase your mileage. Be sure your running a large enough air cleaner and it is clean. A EGR valve can help with fuel economy at cruise speeds. You also want to be sure you have a good tune-up, good sparkplugs, wires, cap and rotor.

Carb spacers can definitely change the performance of an engine. A 4-hole spacer can improve your low end response, but also limit your top end performance some. A divided spacer would do the opposite, you will lose some bottom end performance but you may pick up some performance on the top end. Open spacers are only for use on single plane intake manifolds and will cause your engine to lose some low end response but you should pick up on the top end. Open spacers are very common in racing applications when allowed. You can change the power band of your intake pretty easy, using 1 to 2-inch spacers. The bigger gains will be seen when your intake manifold is a little too small for your application adding this additional plenum volume (open spacer) can really wake an engine up at higher RPM’s.

If this is carb related your calibration might be a little off. First try the different positions on the accelerator pump arm. The top hole closest to the pivot point will give you the biggest pump shot, the bottom hole will give you the smallest pump shot of fuel. In most cases this will take care of the problem. Also, be sure your idle mixture is adjusted properly, the idle mixture still plays a roll right off idle. If these things don’t solve the problem then you will need to recalibrate the carburetor. If you can notice a difference in performance with the different pump arm positions then this will help you. If the top hole closest to the pivot point works the best the engine wants more fuel and if the bottom hole works the best then the engine wants less fuel.

This is normally due to a choke that is slightly out of adjustment, this is common as the temperatures get colder into the fall months. As the temperatures decrease the choke valve will start to close more, when this happens the fast idle cam will engage. The best way to resolve this is to readjust your choke. If the choke is not the cause, then check to be sure the return spring is not catching on anything.

Altitude has a direct effect on the operation of most carburetors. As the altitude increases, the air becomes less dense so a carburetor, originally calibrated at low altitude (sea level), delivers too much fuel and the engine runs richer. If the preceding tuning procedure is performed on an Edelbrock Performer Series/Thunder Series carburetor, a proper high altitude calibration will result. If the vehicle was calibrated at lower altitude, however, and is to be driven at high altitude temporarily, it is not necessary to repeat the complete calibration procedure. A good rule to go by is to adjust your carb “2% leaner per 1500 feet” of elevation you will be traveling to. For example, with a #1405 at baseline calibration (location #1 on the chart) and intended operation at 6000 ft. altitude, you would want 6000 divided by 1500 x 2% = 8% leaner calibration. That would be location #24 on the chart which would require only a rod and jet change.

There can be a few things that can cause no pump shot of fuel through the accelerator pump nozzle. First be sure the pump connector rod is hooked up; this rod connects the throttle lever to the accelerator pump arm. Next, remove the airhorn of the carburetor and inspect the accelerator pump for any obvious signs of a bad pump, like a torn pump cup. Be sure the float level is set to 7/16, if the float level is to low, there will not be enough fuel in the float bowls to fill the accelerator pump well. If float is to low see adjust float procedure. Next, be sure that the accelerator pump passage is clear use some carb cleaner. If the pump passage needs to be cleaned use some carb cleaner with the supplied nozzle spray the carb cleaner through the hole in the bottom of the pump well. You should see the spray coming out of the accelerator pump nozzle. If that passage is plugged take off the accelerator pump nozzle and turn carb upside-down. A check ball and weight or check ball and spring should come out depending on the model of carb. You want to be sure the check ball comes out, if it does not then it may be stuck in the bore and causing your problem. This can be common especially with engines that are not ran much. Use some carb cleaner/penetrating spray to try to free up check ball if needed, then clean passage.

The most common reason the secondary’s do not open is due to an improper choke adjustment or the choke is not opened all the way. When the choke is engaged there is a secondary lock-out that will not allow the secondaries to open. Some other causes could be a throttle cable not adjusted properly or a possibility that the secondary throttle blades are hitting the intake or adaptor. There is also a link on the passenger side that ties the primaries to the secondary’s, be sure this linkage is installed. Note: The secondary air door MUST be opened to see the secondary throttle blades. The air door is not a mechanical device and will not open when you actuate the throttle.

When off-roading in an uphill off camber situation the fuel from one float bowl spills over to the other float bowl due to a passage that ties the 2 float bowls together at the rear of the carb and then the carburetor floods out the engine. This passage can be seen with the top of the carburetor off, its located at the top rear of the carbs base. Here are a couple things that you can do to help make this better. First be sure the floats are set to the recommended 7/16” gap, if float needs to be adjusted see float adjustment procedure. It is also recommended to use the Edelbrock off-road needle & seat assembly #1465, this could also help during off-road use. To help prevent the fuel from flowing through the rear passage it can be blocked off. With the top off the carburetor place a fuel resistant putty or epoxy to fill in the rear passage. We don’t recommend modifying the carb just use something to prevent the fuel flow. Our carburetors are not ideal for extreme off camber situations when off-roading, but if you do these steps it should greatly improve the flooding problem.

Here are a few things that would prevent fuel from entering a Performer/Thunder series carburetor. A stuck Needle & Seat can cause this, first try tapping on the rear of the carburetor with a small screwdriver handle while cranking to try and knock them free. Check the fuel pressure you must have at least 2 p.s.i. of fuel pressure to run the carburetor. If you still can’t get fuel to enter the carburetor, then remove the lid from the carburetor and pull the needle out of the seat. Inspect the needle tip and seat for any obvious signs that would cause the needle to get stuck. Next remove the seat assembly and inspect the screens behind the seat. These screens could be plugged preventing the fuel from entering the carburetor.

If the choke valve will no longer close, then more than likely the choke thermostat is bad and the choke cap needs to be replaced. First, loosen up the 3 screws and rotate the choke cap clockwise to see if the choke valve will close. Also check to see if you can move the choke valve by hand, if you can move the choke valve by hand but can’t move it by turning the choke cap then replace the choke cap #1474.

If you are in an area that does not require a choke it is possible to not hook up the push pull cable. If you’re not using a manual choke push pull cable, then you must wire or secure the choke open in some way. If you do not secure the choke in the open position it can close upon acceleration. One of the best ways to lock the choke open is to use a piece of wire in the hole where the push pull cable goes, then secure it somewhere on the carburetor.

The float level should measure 7/16”. Measure the float level using a 7/16” drill bit between the airhorn gasket and the top of the outer end of the float just past the inboard float radius.

Edelbrock Carburetors can be used with a draw through blower, such as the positive displacement 6-71 type blowers. Edelbrock carburetors can’t be used on blow through blowers because of the hollow float design and non-sealed throttle shafts. Edelbrock has done some testing with #1405 carburetors on 6-71 blowers and below is a combination that worked well during testing. Two model #1405 carburetors should be used on engines with positive displacement superchargers, such as GMC 6-71 blowers or equivalent. The following calibration changes make an excellent starting point: Primary Jets - .101" (#1429); Secondary Jets - .101" (#1429); Metering Rods - .070" x .042" (#1450); Step-up Piston Springs - 5" (orange, stock); Needle & Seat assemblies - .110" (#1466). This calibration has been tested on engines ranging in size from 350 c.i.d. Chevys to 440 c.i.d. Chryslers with good results.

There is no fuel filter inside the Edelbrock Performer/Thunder series carburetors. Screens are installed into the needle and seat assembly, but this is not a fuel filter, the screens are used to trap large pieces of debris. An external fuel filter must be used with Edelbrock carburetors.

The Edelbrock Performer/Thunder series carburetors have vented float bowls so it’s common to smell some fuel fumes, especially under the hood with the air cleaner off. A couple things can compound the smell of fumes and heat soak could be a big reason. With heat soak the fuel in the float bowls heats up expands and can even boil the fuel in the float bowls. When this happens fuel can get forced up through the primaries and float bowl vents. This can cause an extreme fuel vapor smell after the engine is shut down. To help prevent this Edelbrock recommends the use of a heat insulating spacer to help keep carburetor cooler. Another cause of a heavy fuel smell after the engine is shut down is flooding. With flooding you will normally have a carburetor running problem as well. Here are some things to check to resolve a flooding condition.

• Fuel pump pressure is too high. The fuel pump pressure should be no more than 6.5 p.s.i.
• Take the top of the carburetor off and check for debris in the needle & seat, also inspect the needle tip to be sure it’s not compromised.
• While the float is off, shake the float for any signs of fuel in the float. If there is fuel in the float replace float.
• Check float level, the float level should measure 7/16”. Measure the float level using a 7/16” drill bit between the airhorn gasket and the top of the outer end of the float just past the inboard float radius.
• Another cause of leaking fuel could be heat soak. Heat soak is when the heat from the engine compartment heats up and can boil the fuel in the float bowls. When this happens, the fuel can get forced through the venturi booster and drip into your engine. This can also cause fuel leaks through the airhorn gasket. Add link to heat insulator gaskets.

The Edelbrock Performer series #1406 & #1411 carburetors are calibrated lean for fuel economy and in most cases, will not function properly on Performer RPM & Torker style manifolds. Most people think you can just change the calibration of the carburetor and turn it into one of the Edelbrock performance carbs. This is not the case as the Venturi boosters are also different and Edelbrock does not sell Venturi booster separately. In most cases when using one of our economy style carbs on a Performer RPM or Torker syle intakes will cause hesitations and surging in the lower RPM range.

Nitrous oxide is a cryogenic gas composed of two nitrogen molecules bonded to one oxygen molecule, hence, the chemical name of N2O. It stays in liquid form under pressure and converts to a gaseous state when released into the atmosphere. Being 36% oxygen by weight, nitrous oxide is considered to be an oxidizer, not a fuel, and is non-flammable by itself. Because nitrous oxide is a cryogenic gas, the same safety methods in handling dry ice apply to nitrous. Direct contact with the skin will cause a burn similar to contact with dry ice. Nitrous Oxide is offered for sale in two common grades, which are U.S.P., and Nytrous Plus. U.S.P. nitrous oxide is medical grade nitrous oxide. Its common use is dental and veterinary anesthesia as well as use as a propellant in food such as canned whip cream.

U.S.P. is not available to the public and would provide no advantage in the making of horsepower over the automotive grade nitrous oxide. Nytrous Plus was specifically designed for automotive consumption and differs from U.S.P. in that it contains trace amounts of sulfur dioxide (100 parts per million or “PPM”) added to prevent substance abuse. The Sulfur Dioxide is an irritant to all of your breathing passageways and will cause sore throats and sore nasal passages. Nytrous Plus was specifically created for automotive applications and is available for sale to the public at many speed shops across the USA and abroad.

As stated before, nitrous oxide is an oxidizer. An oxidizer supports combustion by supplying additional oxygen. Initially, the nitrous doesn’t help the process. This is because as long as the one oxygen molecule is bonded to the two nitrogen molecules, the oxygen isn’t free to aid combustion at all. Only after they’ve been exposed to the heat of the combustion process will the chemical bond be broken (the bond breaks around 570 degrees), allowing the free oxygen molecule to then contribute to the combustion process. Additional fuel is added along with the nitrous to maintain a stoichiometric air/fuel ratio. The end result is more horsepower being created pretty much the same way a blower or turbocharger does.

Bottle pressure is one of the most important factors in tuning a nitrous oxide system. Many people feel that if a bottle is full then the pressure must be right, however, that isn’t always true. Pressure has a direct relationship to temperature. A full bottle can vary from 750 to 1200 psi depending of the method used to fill the bottle. All Edelbrock nitrous systems are tuned utilizing liquid nitrous, which is denser than gaseous nitrous as well as more stable. Nitrous becomes a liquid at a temperature of –127°F at atmospheric pressure. Since this temperature is nearly impossible to sustain and there would be no pressure to carry the nitrous where it needs to go, we use the alternate method to change the phase to a liquid by pressurizing it to a level of 735 psi or greater, ideally 950 psi. At 950 psi nitrous has a density of 5.44 lb/gal., bottle pressure is more stable and can easily be sustained with the use of a bottle heater. Many people also feel that running pressure greater than 950 psi will generate much higher flow of nitrous, however, this is not the case.

Figure 1 below illustrates the relationship between bottle temperature and bottle pressure. Note that as volume decreases it is harder to maintain pressure and a bottle heater can help ensure better consistency. A consistent bottle pressure provides a consistent amount of nitrous delivered during a given period of time. It’s also good practice to top off the bottle when it reaches a volume of less than 40%. Although a pressure of 950 psi can be achieved at almost any volume, the problem is that the pressure drop will be much greater than when a bottle is full, and consistency can be affected.

When we set the timing on a car we are actually finding the point in which the engine will initiate the burn so that at about 15° After Top Dead Center (ATDC) peak cylinder pressure can occur. Depending on combustion chamber design and cylinder filling, this point can be anywhere between 30° and 45° Before Top Dead Center (BTDC). The reason we retard timing with nitrous injection is that the air charge becomes more oxygen dense, causing the air/fuel mixture to burn at a much higher rate. In other words, accelerated combustion occurs. This acceleration in combustion causes peak cylinder pressure to happen much earlier. The problem with this is that instead of using the energy generated by combustion to give the piston momentum we are transferring that heat energy onto the rotating and reciprocating assemblies, and possibly hurting them. In the process we are losing torque and horsepower. To prevent this, we recommend that you retard the ignition timing 1-1/2° to 2° for every 50 hp added through the nitrous system. This will ensure that peak cylinder pressure occurs at the same point it did before the nitrous was injected into an engine. Also keep in mind that retarding too much timing will also hurt you. If you retard more than the recommended amount, peak cylinder pressure can occur much later in the combustion cycle and that energy will be wasted. In most cases, avoid aftermarket chips or computers that are not designed for use with nitrous. They typically add more ignition timing, which could lead to power loss and engine damage.

The last frequently misunderstood factor in adapting a nitrous system to your engine is the spark plug. Three important aspects of spark plugs must be looked at: their heat range, reach and gap. We advise lowering the heat range of your spark plugs 1 step for every 100 hp added with nitrous. The other aspects of a plug that must be looked at are the reach and gap. It is best to use a non-projected type plug. Projected plugs allow a greater portion of the electrode to be exposed to combustion gases and possibly cause pre-ignition. The spark plug gap also plays a large roll in nitrous engine performance, because increased cylinder pressure from the additional nitrous and fuel makes it harder for the spark to jump the gap. The same gap that worked for a non-nitrous set-up may be too much for nitrous, leading to excessive misfires and loss of power. Also, we recommend that you do not use platinum plugs. The platinum tips can get extremely hot and will cause detonation. Plus, there is a chance the tip may break off in cases of mild detonation and can severely damage the engine.

Ideally a gap between .025" and .035" should be used on high horsepower applications where an inductive style ignition system is utilized. Engines equipped with capacitive discharge ignition systems may use gaps larger than .035". It’s very important to learn how to read the plugs after a pass. A plug can tell you a lot of what is happening in the combustion chamber.

A common and often overlooked problem is insufficient fuel pressure. For nitrous applications we must determine if your fuel sytem is adequate for the task. Most modifications will be fine on factory fuel delivery systems. On highly modified engines that horsepower levels exceed 40% over the manufacturer rated hp level, modifications like the addition of an in-line booster pump or dedicated fuel system is recommended. The purpose of a booster pump is to work in conjunction with the stock pump and maintain a more consistent fuel pressure. The booster pump allows the factory pump to provide its maximum volume capacity; the booster pump then increases the fuel pressure. In racecar applications with a direct port nitrous system or wet nitrous system, a dedicated fuel system is recommended. A dedicated fuel system consists of a fuel pump, fuel pressure regulator and feed line to the fuel solenoid. The purpose of a dedicated fuel system is to provide fuel enrichment for the nitrous system independent of the primary fuel system. A dedicated fuel system offers a greater degree of tune-ability and eliminates problems that might arise from sharing a fuel pump with the engine.

With all nitrous oxide applications, forged pistons are highly recommended. Because of heightened potential for detonation, cast pistons are more prone to failure and cannot handle horsepower increases over 125 hp. Never initiate your nitrous system before you are at full-load, wide-open throttle conditions. Cast pistons will not be able to survive this kind of stress.

With a dual-plane intake manifold you should not exceed 175HP shot of nitrous through a plate system. If a larger than 175hp shot is used with a dual-plane intake is used you will start to have distribution issues and could potentially damage your engine. A single plane intake manifold should be used for higher horsepower nitrous plate applications or if a dual-plane intake must be used switch to a direct port nitrous system.

With a Edelbrock wet plate system there is no need to recalibrate the carburetor. With a wet plate system, the extra fuel is supplied through the plate.

As a general rule, do not exceed 6% fuel pressure drop when the nitrous system is activated. For example, if the OEM states that 45 psi is an acceptable fuel pressure for a given vehicle, the fuel pressure drop seen when the nitrous system is activated should be no more than 2.7 psi on EFI-equipped vehicles. On carbureted applications with 7.5 psi, a drop of no more than .5 psi is acceptable

Always use Teflon paste on all pipe fittings. Never use any kind of thread sealant on taper seal fittings like a jet fitting, or bottle line connections.

Do not offer a jet map for the lower bottle pressures. Always keep your bottle pressure between 900 and 950 psi when using the nitrous system. Yes, there are racers that use different pressures, but the testing we did here at Edelbrock to ensure the jetting maps within our manual are correct and was done in this pressure range. Use any higher pressure than 950 psi and you will be lean. Use any pressures below 900 psi and you will be rich. Edelbrock offers a bottle heater to help maintain bottle pressure in colder weather #72700.

The general rule of nitrous as it relates to ignition timing should be to retard the “Total” advance number approximately 2 degrees for every 50 HP increase when using nitrous oxide. It is always best to start with your engines best total timing (without nitrous) and reduce total timing from there. Use an initial timing retard setting that is at least 2-4 degrees more retarded than you expect to be the best setting for your application. All stated timing adjustments listed in jet maps is where the motor being tested worked best.

Ideally a gap between .025" and .035" should be used on high horsepower applications where an inductive style ignition system is utilized. Engines equipped with capacitive discharge ignition systems may use gaps larger than .035". It’s very important to learn how to read the plugs after a pass. A plug can tell you a lot of what is happening in the combustion chamber.

Always keep your bottle pressure between 900 and 950 psi. Yes, there are racers that use different pressures, but the testing we did here at Edelbrock to ensure the jetting maps within this manual are correct, was done in this pressure range. Use any higher pressure than 950 psi and you will be lean. Use any pressures below 900 psi and you will be rich.

Always ensure you have between 6 and 6.5 psi of fuel pressure every time you enable your nitrous system. We used 6 to 6.5 psi of fuel pressure to perform our jet map testing on this system. If you do not have at least 6 psi of fuel pressure going to the fuel solenoid, when it is activated, you will be lean. If you were to have more than 6.5 psi of fuel pressure, when it is activated, to the fuel solenoid, you would be rich.

If the bottle is mounted inside the passenger compartment or in a space that has access to the passenger compartment such as hatchbacks or vehicles that feature fold down rear seats, the pressure relief device (PRD valve) must be vented externally from the cockpit. To do this use Edelbrock Nitrous blow down tube #72960 and Racer safety blow-off adaptor #72961. These kits will work on Edelbrock 10, 15 and 20-lb. bottles. This procedure will prevent the passenger compartment from filling with a cloud of nitrous oxide, should the safety pressure relief valve rupture. Special consideration should be made to protect the bottle installation by not placing the bottle in a known crumple or crash zone within the vehicle. At no time should the bottle be mounted within the seating area of the passenger compartment of a street-driven vehicle.

With the Edelbrock plate system we recommend setting the fuel pressure flowing through the plate. To do this have the plate over a bucket or cookie sheet activate the fuel system and adjust pressure regulator until the desired pressure is achieved flowing through the plate. If this method is not used you may see a pressure drop when the fuel is flowing through the plate during the use of the nitrous system.

First you need to verify the bottle pressure is between 900-950 p.s.i. and your fuel pump pressure is between 6-6.5 p.s.i. If the bottle or fuel pump pressure is off it can definitely cause a surge. Next check all fuel filters and fuel delivery. Double check spark plug gap, the gap should be between .025” & .035”, if the spark plug gap is too great then the spark could blow out due to the higher cylinder pressures. Take the spray bar plate off and check the spray pattern off the plate, to be sure you don’t have a blockage in the spray bars. Be sure your nitrous bottle is full and be sure the mounting of the bottle is correct.

The solenoids are reverse polarity so it does not matter what wire is hooked to ground or power.

Bottle placement is critical to the performance of your nitrous system. It is important to understand how the bottle valve and siphon tube are assembled to properly orient the bottle in your vehicle and ensure that it picks up liquid nitrous while undergoing acceleration. All nitrous bottles are assembled so that the bottom of the siphon tube is at the bottom of the bottle and opposite of the bottle label.

An Edelbrock nitrous bottle cannot be mounted upside-down. Edelbrock does not offer a non-siphon tube bottle for automotive use. If the bottle must be mounted parallel to the axles of the vehicle (sideways), the valve handle and label must be angled at approximately 45 degrees toward the front of the vehicle. This orientation will position the siphon tube toward the rear and pointing to the lower rear facing quadrant of the bottle. All of this positioning information is critical to system operation. It is important to draw as much liquid nitrous as possible. The siphon tube cannot do this unless the bottle is positioned correctly.

The most efficient mounting is the lay-down position with the valve handle toward the front of the vehicle and the bottle label facing up. This position allows the greatest amount of liquid to be used before the siphon tube begins to pick up gaseous nitrous oxide.

The jet fittings are color-coded for use with nitrous (blue) and fuel (red). The red fitting faces the front of the engine and the blue fitting faces the rear. The plate has been etched indicating which of the gasket surfaces face upward. Look at the brass tubes, a properly oriented plate will have the nitrous tube above the fuel tube ensuring the angled orifices machined into the tube face orient to the floor of the intake manifold.

The main benefit of a direct port nitrous system is the ability to tune individual cylinders. The direct port systems are also capable of supplying a bigger shot of nitrous over a plate system.

The main benefit of a Nitrous plate system is ease of installation, no plumming of hard lines and easier to make jet changes. A nitrous plate system will give you a harder hit off the line in comparison to a direct port system.

With a wet nitrous system, the fuel and nitrous are supplied through the nitrous system. One of the more common ways to do this is through a nitrous plate. The plate injects both nitrous and additional fuel using one nitrous spray bar and one fuel spray bar. Both sides are metered by tuning jets as they’re sprayed into the incoming air charge. With a dry nitrous system, the nitrous is metered by tuning jets and injected through a dry nozzle (no fuel) into the incoming air charge. The nitrous system interfaces with the EFI system and increases fuel flow to the existing fuel injectors when the system is armed and triggered.

In most cases you should not have nitrous engaged for more than a ¼ mile run or about 15 seconds.

For nitrous applications running over a 100 shot of nitrous, an aftermarket high performance ignition system is required.

It’s not a requirement to run a purge valve kit for non-competition use, but the purge valve kit has benefits. The Purge Valve Kit is designed to vent gaseous nitrous to the atmosphere to fill the nitrous feed line with liquid nitrous for a better nitrous charge when the nitrous system is in use. This will give you more consistent nitrous passes and is a must for competition use. Be sure the nitrous purge line is mounted on the vehicle so the spray direction is not pointed in a direction which could fill the passenger compartment with nitrous oxide.

Running a fuel pressure switch is not required but would be highly recommended. It’s nice knowing if you do have a problem with the fuel system pressure the nitrous will disengage before engine damage occurs.

To enter the options menu, hold down the ENTER button after turning on the unit. The display will blink several times then display RELEASE. When the button is released you will be in the options menu. Use the function button to go through the options.

If your progressive controller’s active display flashes on and off or resets itself during operation causing the vehicle to surge, it may be caused by electromagnetic interference generated by the engine’s ignition system or other vehicle components.

Do not mount the progressive controller anywhere near ignition components or any other source of electronic noise. If you have difficulty isolating the controller from RF/EM interference, it may help to mount the controller in the rear portion of the interior as far from the firewall, ignition components, and wiring harnesses as possible. Controller should be mounted on flexible rubber mounts or Velcro to assure the housing is not in contact with the vehicle chassis or other common ground plane.

Static suppression ignition wires and resistor type spark plugs are highly recommended for use with this controller.

If your progressive controller’s active display flashes on and off or resets itself during operation causing the vehicle to surge, it may be caused by electromagnetic interference generated by the engine’s ignition system or other vehicle components.

No battery or power connection is needed to retain the controllers parameter settings. There is no need to re-program the controller after the battery is disconnected. There is NO internal battery, all data is stored in flash memory and will be retained for up to 10 years with no power applied to the controller.

Transient fuel controls the fuel metering in throttle opening events. You can think of this as an accelerator pump on a carburetor.

Global modifiers such as Global Fuel & Global Spark control the overall value in the map. A change here will affect every cell of the appropriate map. Ex: if you add 10% Global Fuel, the entire engine range will be 10% richer, Cold Start, Idle and WOT.

Here is a basic guideline: Idle: Don’t watch LED’s, tune for highest vacuum Cruise: Toggling between Amber & Red WOT: Green Decel: Red

This is normal. The Calibration Module uses 220 as a resting constant. As soon as engine RPM exceeds 220 the Calibration Module will display accurate RPM.

It is mandatory that the distributor be set to 10 degrees before top dead center (TDC). The ECU assumes this 10 degree timing in all spark advance calculations. The spark advance value in the first display screen has this 10 degrees of distributor advance already included. Located in the “MISC. MODIFIERS” submenu is the function “BASE TIMING SET”. “Base timing” refers to mechanical distributor timing only without any electronic spark advance. This function should only be used to set the distributor timing. With base timing ON, run the engine at about 1500 RPM, and using a timing light, set the distributor to 10 degrees before TDC. WARNING: DO NOT drive vehicle with base timing ON. Serious engine damage may result. Safeguards are built into the system to make it almost impossible to have the base timing function ON without you knowing it. Exiting out of this screen is prohibited if base timing is ON. All SAVES to permanent memory are done with base timing forced OFF. After the distributor timing is set and the hold-down plate is tightened, turn OFF the base timing function.

10° is a reference that the ECU uses to properly phase the timing. The ECU controls the engine timing. The engine will actually never be at 10° unless Base Timing Set is turned on in the Calibration Module.

This is something that is not used. It was deleted in development but never got removed from the Calibration Module. Pay no attention to it.

Static pressure (Key on, engine off) is 42-45psi. 32-38psi with the engine running.

You can refer to the calibration selection guide on the disc or call the tech line for a calibration recommendation.

This is caused by supplying the ignition coil with a separate 12v power feed. This causes voltage to back-feed into the system and keep it energized. There should only be two wires going to the coil, both coming from the ProFlo harness (A tachometer wire going to the – side of the coil is ok).

This is most likely caused by not enough throttle blade opening. When the blade(s) are closed the IAC motor has to control all the air coming through the engine, this is what is causing the noise. The throttle blades should be cracked a little. Follow the idle set up procedure in this Q&A.

The Edelbrock cylinder heads are made in the USA. The heads are casted in our ultramodern foundry in southern California and then machined and assembled at our headquarters here in Torrance California, USA.

In most cases the stock valvetrain will need to be changed. Most Edelbrock heads require adjustable valvetrain, in other cases the heads might take special valvetrain. To find out what valvetrain is needed see instruction sheets or contact Edelbrock Tech line.

To figure out what the compression ratio is with Edelbrock heads your best bet is to call the piston manufacturer. Just tell the piston manufacturer what the combustion chamber volume is on the Edelbrock heads. You should also have the info on the compressed head gasket thickness and piston part number before you call the piston manufacturer. There are also compression ratio calculators that can be found online that can be helpful.

Hardened pushrods must be used with Edelbrock heads if the heads use pushrod guide plates.

The recommended spark plugs are Champion RC12YC/2071 or equivalent 14mm x 3/4” reach with a flat gasket seat.

All the Edelbrock Performer, Performer RPM and E-series heads have stock intake and exhaust port locations. A lot of the Victor Jr., Victor and some E-CNC do not have stock port locations. Look in the cylinder head specifications for information or contact the Edelbrock Tech line.

Most of today’s coolant will be compatible with the Edelbrock cylinder heads. Just be sure the coolant is designed to be used with aluminum engine components. If you do not buy the premixed coolant be sure you mix the coolant with 50/50 mix, distilled water.

Edelbrock recommends the use of stock ratio rocker arms with Edelbrock cylinder heads. The design and testing has been done with factory ratio rocker arms. If a higher ratio rocker arm is used in some cases pushrod length may have to be changed and you could run into a clearance problem with the pushrod hole in the head.

Generally, you can expect to see gains around 30-50 hp over factory cylinder heads, but this depends on a lot of variables.

Bare cylinder heads will have guides and seats installed, but will require final sizing and a valve job to match the valves you will be using.

Edelbrock offers different spring options for most of our cylinder heads. However, Edelbrock E-Street heads only allow springs for hydraulic flat tappet cams.

With a straight cut .060” will be the max that can be machined off the deck. With an angle mill .120” will be the max that can be machined off the deck.

The spring pockets can be machined up to .060” deeper with Edelbrock Street heads like (E-Street, Performer, Performer RPM). Contact Edelbrock Tech support for information on the race series heads like (Victor Jr and Victor series).

To be safe Edelbrock recommends running .100” piston to valve on the intake and exhaust. Some engine builders will run tighter clearances but .100” will be a safe clearance.

The 2.02” intake valve will not clear the factory pistons unless they are notched for the 2.02” valve.

The Edelbrock cylinder heads can be used on the 350-403ci. engines with some modifications. The mechanical fuel pump can’t be used, must use an electric fuel pump. Must use the RPM intake manifold and port match the intake to the heads. In some cases, the factory brackets will not fit if they attach to the cylinder head.

When using the Edelbrock #9680 head bolt bushings a head bolt washer is no longer needed. The #9680 will take the place of the head bolt washer.

It is not a problem to block off the exhaust crossover on Edelbrock heads. If it’s for non-emissions use only and you don’t have to have the exhaust heat to operate a heat activated choke or EGR valve.

The E-street heads are rated to 5,500 RPM’s due to the valvetrain that is used. The E-street heads use a harder seat and a heavier valve in comparison to our heads that are rated to higher RPM’s. The E-street heads start to encounter valve float past 5,500 RPM’s.

The E-street heads use a harder seat and heavier valve, for this reason we do not recommend running a roller cam. With the more aggressive ramp designs of the roller cams you will run into valve float quicker and may encounter engine damage.

If pushrod rubs on the cylinder head, remove rocker arms, loosen the rocker studs and move the guideplate as needed to provide clearance. After checking all pushrods for proper clearance, ensure that the tip of the rocker arm is making adequate contact with the tip of the valve stem. Carefully re torque to 45 ft./lbs. any rocker studs that were loosened. Check alignment again to be sure that the guideplates did not move while torqueing the studs.

The spark plugs are not in the stock location, they are an angle plug design to make more horsepower. For headers, we recommend contacting TTI (951) 371-4878 they have headers designed to fit the Edelbrock cylinder heads, or call Tech Department.

With these heads, a Ram-Air IV (round port) design header or exhaust manifolds must be used.

One of the more common reasons an engine would run hot after cylinder head installation is due to air trapped in the cooling system. Get the front end of the vehicle up in the air using some wheel ramps. With the engine cold remove the radiator cap and start the engine for a couple minutes. Doing this will work the air pockets out of the cooling system, refill coolant as needed. Be sure the thermostat was installed correct also.

Due to the rate at which aluminum dissipates heat you can get away with running a higher compression ratio over cast iron heads. To be safe you can run a half point higher compression ratio with Edelbrock heads over cast iron heads.

Edelbrock does not offer a cylinder head repair service.

More than likely the area the intake manifold is not covering is a blind expansion chamber around the exhaust crossover. The intake does not have to cover this area its just an expansion area around the exhaust crossover just be sure the cavity is blind and does not go anywhere.

With the Edelbrock FE cylinder heads there is no reason to restrict the oil feed with what we have seen during testing on Edelbrock dyno’s and in car testing.

These cylinder heads are equipped with valve spring cups. Due to the diameter of the valve spring cups, it may be necessary to clearance the headbolt washer. This will allow the headbolt washers to seat properly to the cylinder head. This can also be accomplished by removing the valve spring and cup. Then position washer prior to installation of cylinder head.

The heads are designed to use non-self-aligning rocker arm. If self-aligning rockers are used the guideplates will need to be removed and replaced with some hardened washers, like head bolt washers.

The valve seat angles on Edelbrock street complete heads are; 30°, 45° (on seat) and 60°. Edelbrock racing heads may use different valve seat angles, contact tech department for more information.

Edelbrock crate engines are assembled with all new parts.

There is no core charge for Edelbrock crate engines as they use all new parts.

The Edelbrock crate engines that use a flat tappet cam will need to break-in the cam. If you pay for the dyno service there will be no need to break-in the cam, we break-in the cam before the dyno pulls. No need to break-in the camshaft with engines equipped with a roller cam.

Edelbrock crate engines are not ran before they are shipped, unless you pay for the dyno service.

Edelbrock crate engines that are above 400 horsepower will require the use of a higher stall speed torque converter. Normally recommend a stall speed around 2,500.

The carburetor settings should be close out of the crate. The only adjustment that would be required is the choke. The outside temperature determines the choke position so due to different climates we can’t preset the choke. The best time to set you choke is in the morning when the engine is cold and the outside temps are on the lower side. With no power supply to the choke hit the throttle, the choke should close and you should have about an 1/8” gap between the choke valve and the airhorn. If your choke is out of adjustment just loosen the 3 choke cap screws and rotate the black choke thermostat until you achieve a 1/8” gap. If you must adjust the choke be sure to hold the throttle lever open about a ¼ of the way. This will ensure that the fast-idle cam is out of the way and will not interfere with your adjustment. If the choke is adjusted properly and it still will not open fully, you may have a problem with the voltage supply to choke. The choke needs a key on 12-volt power source. This means it is necessary to have 12 volts while engine is running and no power when the engine is off. With the wire disconnected from the choke check to be sure you have 12 volts when the key is on. If not find a new power source. Do not connect the positive wire to the Ignition Coil, ballast resistor or Alternator.

The Edelbrock crate engines are supplied with Edelbrock Break-In Oil in the crate. The engine oil must be changed no more than 300 miles after break-in. After 250 to 300 miles the engine will be broken-in.

Zinc Enhanced 10w-40 motor oil is recommended for most climates to provide the necessary wear protection that is no longer found in most conventional oils.

The recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4” reach with a flat gasket seat.

If you have no engine in your application and need to check fitment you might want to invest in a mock up block. They are great for checking clearances and are light weight.

The Edelbrock Supercharged LS 416 crate engine uses a Corvette belt offset.

The Edelbrock supercharged LS 416 crate engine made 12 pounds of boost on the Edelbrock dyno at sea level in a controlled environment. Boost numbers can vary depending on variables like elevation, outside temperature and humidity.

The Edelbrock supercharged LS 416 crate engine can be ordered with a different supercharger lid that will give you an additional 2” of clearance. When you order the engine just tell the place of purchase that you would like to special order the engine with the corvette supercharger lid. Here are the specs of the engine as it ships without the corvette lid. Top of supercharger measures 21.54" from crank centerline, Oil pan dimensions: 2.625" tall at the front, sump measures 6.75" (front) to 7.75" (rear) high and 7.75" in length.

The Edelbrock supercharged Ford Coyote 5.0L crate engine made 17 pounds of boost on the Edelbrock dyno at sea level in a controlled environment. Boost numbers can vary depending on variables like elevation, outside temperature and humidity.

The Edelbrock supercharged crate engines must run a minimum of 91 octane fuel.

Please note that this crate engine is originally from a 2011-13 5.0 Mustang equipped with electric power steering. In order to run power steering, you can retrofit an appropriate electric power steering pump. Another option is to use the Ford Racing Power Steering Pump Bracket for the 2011-2013 5.0L. This bracket can be purchased directly from Ford Racing (Part Number - M-8511-M50BR). Please note that the Ford Racing solution mounts the power steering pump in the A/C compressor location. As a result, the Ford Racing bracket is not compatible if you will be running A/C.

This crate engine is shipped dry without engine oil. Make sure to add the recommended Ford oil prior to priming the engine oil. The engine oil must be changed no more than 300 miles after break-in. A full synthetic SAE 5W-50 is highly recommended after the break-in period. Engine oil capacity is eight (8) quarts.

The Edelbrock #1207 air cleaner as designed as a stock or factory replacement air cleaner. With that, additional parts will be needed to use on an Edelbrock carburetor. To use an Edelbrock electric choke carburetor spacer part #8092 is required. To use on a manual choke carburetor Edelbrock banjo fitting part #8089 is required.

This exclusive urethane foam element retains its high filtering efficiency when washed at 2000 mile intervals. Geographic location and/or vehicle usage may require more frequent cleaning. Simply remove filter by releasing one spring clip, then wash in hot soapy water. Allow element to dry, then re-assemble. When needed, replacement filters (Edelbrock #1099) are available.

The base of the air cleaners for dual-quads is not adjustable, the base spacing is fixed at 6-7/16”, for all Edelbrock brand Dual-Quad intake manifolds.

Hold down tabs should be used when using Edelbrock Signature series stamped steal valve covers. The hold down tabs will help spread the load of the bolts and ensure a good seal.

If the cover is hitting the plenum, then a spacer will need to be used to space up the upper plenum. Before installing a spacer to raise your upper plenum verify hood clearance. Edelbrock offers some plenum spacers for Edelbrock intake manifolds.

Edelbrock tall profile valve covers will have enough clearance to work with roller rocker arms. Due to different designed rocker arms, double check clearance to valve cover baffles.

For applications using breathers/PCV, attach the breather baffles using the supplied drive pins or self-tapping screws. If your valve covers include drive pins, use a punch and hammer to tap the pins in until fully seated. When driving the pins into the valve cover, you must support the back side of the valve cover with a block of wood, or other non-marring surface. Failure to do so could result in damage to the valve cover, such as cracks, dents, etc.. Some valve covers include baffles with a curved recess across them. Make note of the position of the baffle. The recess in the baffle plate should be positioned as shown below.

The conical air cleaners are a universal design with three inlet adaptors rings for use on 3”, 3.5” and 4” inlet tube systems.

These covers are intended for custom hot rod applications. As such, they may not clear all the hoses, emission hardware, and/or accessories found in a stock application. Modification of the covers may be necessary for use in such an application.

If a lot of oil is being sucked through the PCV valve, then a baffle may not be installed in the valve cover, or installed incorrectly. Also, be sure the PCV valve is functioning properly.

Valve cover gaskets can be installed dry. Some engine builders like some sealer like Gasgacinch to hold the valve cover gasket in place on the valve cover, from the head to the valve cover gasket should be installed dry.

Do not sell replacement elements for the Edelbrock valve cover breathers. The element should last for several years. If you have an Edelbrock breather with a removable top, some foam used to make some universal air cleaners can be used (commonly found in motorcycle parts stores). Make sure foam is gas/oil resistant and won’t cause harm to engine etc.

Take a few pieces of clay, form them into cones and set them on your air cleaner. Then, gently close the hood all the way Making sure you feel for obstructions. If an obstruction is felt stop so you do not cause damage. Re-open your hood to see compressed clay so you can measure it to check for hood clearance. If you don’t have clay handy you can do the same thing by balling up some foil balls.

An oil or additive with a zinc enhanced formula must be used with flat tappet cams. Edelbrock offers a High Performance Zinc Additive #1074 that is designed for hot rods, sports cars, muscle cars and exotics. With a special formula of zinc, phosphorous and moly, it's the ideal chemistry to add wear protection to any motor oil. Because it won’t rub, scrape or wear off, it is perfect for cold starts and infrequently driven vehicles. Also extends engine life and increases mileage and horsepower. One bottle treats up to 6 quarts/liters of oil.

Below is the lifter pre-load recommended for Edelbrock cam and lifter kits.

• Performer plus camshaft and lifter kits, lifter preload should be a 1/2 turn past 0 lash.
• Torker plus camshaft and lifter kits, lifter preload should be a ¼ turn past 0 lash.
• Performer RPM camshaft and lifter kits, lifter preload should be a ¼ turn past 0 lash (except 7106 should be a ½ turn).
• Rollin’ Thunder camshaft and lifter kits, lifter preload should be ¾ to 1 full turn past 0 lash.

Rotate the engine over until you are on top dead center of the compression stroke on #1 cylinder, both valves on # 1 cylinder should be closed at this point allowing both intake and exhaust vales to be adjusted. Spin the pushrod on #1 cylinder with your thumb and index finger, then adjust the rocker arm adjusting nut until you feel drag on that pushrod (not until the pushrod stops spinning). Once you feel the drag you have reached 0 lash and are ready to make your valve adjustment, complete for both intake and exhaust pushrods. With degree tape installed on your harmonic balancer, you can now rotate the crank 90° and adjust the next cylinder in the firing order. Continue to rotate the engine 90° following the engines firing order until all cylinders are adjusted.

Edelbrock recommends stock ratio rocker arms to be used with Edelbrock camshafts. The use of higher ratio rocker arms will change the listed cam specs. Another problem with a higher ratio rocker arm is the added load on the camshaft lobe. A higher than stock ratio rocker arm will put more load on the cam lobe and cause camshaft failure.

With an Edelbrock Performer RPM camshaft a 2,500 stall speed torque converter is recommended. Any torque converters with a stall range from 2,200 to 2,800 rpm would be acceptable.

Stock heads will need to be modified to run a Performer RPM camshaft. Below are some things that will need to be modified on stock heads.

• Valve springs will need to be changed to have the correct pressure and handle the added lift.
• All Performer RPM camshafts require the use of adjustable valvetrain.
• If the heads have rocker studs they must be screw in style. Will not work with pressed in studs unless the rocker arm studs are pinned/or studded.

Edelbrock recommends using the straight up position on the timing chain set. Edelbrock do not recommend advancing or retarding camshaft timing.

Many things can cause engine backfires, below will go over a few things that can cause backfires after a camshaft is installed.

• Double check valve adjustment. Over adjusted lifters can hold valves open and cause the engine to backfire. A leak down test can help determine if valves are being held open.
• Be sure the timing chain/camshaft was installed correctly. If the camshaft is installed incorrectly this will lead to the valve opening at the wrong time and can cause the engine to backfire.
• Double check for vacuum leaks. A vacuum leak can cause low vacuum and create a lean condition and can cause engine to backfire.
• Listen for any signs of a camshaft going flat like noisy valvetrain. If the cam lobes are going flat this can also create a backfire.
• Check your carburetor calibration and operation. A rich or lean carburetor can also cause engine to backfire. Also, be sure the carburetor is not flooding.
• Be sure the distributor is installed correctly and the firing order is correct. This can cause an engine to backfire.

Below are some things to check.

• First be sure cam was broken-in properly. If the cam was not broken in properly, most likely the cam is going flat. See How do I break in my cam for more info on breaking in a camshaft.
• Be sure your running the correct valve spring pressures and the springs can handle the camshaft lift.
• Be sure the rocker arms are not hitting the valve covers or valve spring retainer. Also, be sure the slot in the rocker is long enough to handle the lift and the rocker is not binding on the rocker studs.
• If guide plates are being used, be sure the rocker arms are non-self-aligning.
• If stock heads are being used with rocker studs, be sure they are thread in rocker studs if they are pressed in and running a high lift cam, the studs will need to be pinned/studded or converted to screw in rocker studs.
• Was piston to valve checked, the minimum intake clearance should be .100” and the minimum exhaust clearance should be .100”.
• Be sure the timing chain/camshaft was installed correctly.

With the distributor removed use an oil pump priming tool to prime the engine. Once the drill motor bogs down, continue to prime engine for 15 seconds after the drill motor bogs down then stop. This will ensure all the bearing journals/oil galleys have adequate oil. It is not necessary to prime the engine until oil comes out of your pushrods. Too much oil priming is not a good thing, due to the fact you’re going to wash away the assembly lube.

Make sure the engine starts right away. Long durations of cranking engine will wipe lube off the cam and can cause cam failure. Do not allow the engine to run under 2000 rpm for the first 1/2 hour. Slow idle speeds may result in severe cam and lifter wear. Start the engine and bring to break-in rpm. During the break-in period, it best to continuously fluctuate the engine speed between 2,000 and 2,500 RPM’s. This will help ensure the lifters keep spinning in the lifter bore. Break in not required for roller cams.

The assembly lube should be used in the following areas when doing a cam and lifter install.

• Coat all the lobes and bearing surfaces with assembly lube.
• Apply a thin layer of assembly lube to the crank seal.
• Apply assembly lube to both ends of the fuel pump pushrod, if applicable.
• Apply assembly lube to the cam face of the lifter and side body.
• Apply assembly lube to both ends of the pushrods.
• Apply assembly lube to the distributor gear.
• Apply assembly lube on the valve stems and rocker studs.
• Apply assembly lube on the underside of the rocker arm ball and pivot if applicable.

Below are some things to check for bending pushrods.

• Be sure the springs you are running are correct for the camshaft and you’re not running into coil bind or valve float.
• Be sure the piston to valve clearance is correct, must have clearance of .100” intake and .100” on the exhaust.
• Be sure self-aligning rocker arms are not being used with guide plates.
• Be sure the timing chain set is installed correctly.
• Be sure you have clearance between the rocker arms and valve cover.

A lighter spring is not a bad idea for cam break-in, but is not required. If the recommended spring pressures are used and proper cam break-in procedures are practiced it will not be a requirement to change springs for break-in.

Minimum intake valve clearance should be .100”. Minimum exhaust valve clearance should be .100”. Some engine builders may run tighter clearances but the .100” clearance will ensure adequate piston to valve clearance.

Edelbrock lifters are an anti-pump lifter design, these lifters should not be pumped up, primed, or soaked in oil. If the lifters get pumped up before the installation, the lifters will become solid and you will not be able to adjust the lifter preload, the valve will just be opened when valve adjustment is performed.

A good starting figure would be between 10 degrees to 14 degrees initial timing at idle with vacuum advance disconnected. Total advance should not exceed 32 to 36 degrees with initial and centrifugal weights combined and should be at full advance at 3000-3500 rpm. These are guidelines refer to camshaft instructions for specific settings especially for total timing.

One of the more common reasons this would occur is due to a camshaft being installed incorrect. You should verify the timing chain installation is correct per the manufactures or Edelbrock instructions, be sure the keyway location is correct. Also, be sure the distributor is in correct and you are running the correct firing order.

Edelbrock Performer plus camshafts can be used with new factory valve springs installed at factory specs in most cases. Check spring coil bind to ensure the springs can handle the added lift.

When installing retro-fit lifters that use a tie-bar, it is critical that the arrow on the tie-bar point up towards the intake manifold when the lifters are installed. This should orient the Edelbrock logo on the tie-bar so that it can be read right-side up. When installing retrofit hydraulic roller lifters, make sure the guide bar faces the opposite side of the block. (Example: If facing the front of the engine, lifters being installed on the left side should have guidebars facing the right side of the block). Failure to orient the lifters properly can cause damage to the camshaft and other engine components.

To use Edelbrock springs on stock heads, the valve guides will need to be machined for PC (perfect circle) seals and the seal must be installed before new valve springs can be installed.

If proper break in oil is used and break-in procedures are followed it’s not a requirement to remove the inner valve spring for the camshaft break-in. For added assurance the inner valve spring can be removed during the camshaft break-in, but is not a requirement.

The Edelbrock #5722 valve springs in some cases need the retainers #9733 to add .100” of installed height.

The embossed bead of the intake gaskets should face up towards the intake manifold.

There are a couple steps to ensure you get your intake gaskets sealed up properly, below we will go over the steps.

• Coat head surface and cylinder head side of intake gaskets with 2 coats letting dry between coats Edelbrock Gasgacinch #9300
• Within a few minutes gaskets and surface will become tacky to the touch. Carefully place gaskets on head surface, aligning ports and bolt holes.
• With Gasket in place apply a small amount of RTV High Temp silicone sealer around water passages (intake manifold side only)
• With Edelbrock manifolds, you must use RTV High Temp silicone sealer instead of end seal gaskets. Apply a 1/4" thick ribbon of sealant across each end seal surface. Some installations will require 02 sensor safe silicone.

If the head or intake manifold has no provisions for an exhaust crossover, then there is no need to run the restrictor plates. In most all other cases, the restrictors should be used, one of the only times the restrictors would not be used is if the application is always driven in cold freezing weather.

They are installed by punching out the center hole of the intake gaskets and mating the restrictors together by folding over the small tabs. The use of restrictors is not required but are recommended for warmer climates.

In most cases Edelbrock head gaskets should be installed dry. Some engine builders may use a light coating of copper spray on the cylinder head gaskets, but Edelbrock recommends installing them dry unless otherwise noted in the cylinder head instructions.

Head gasket re-torqueing is not required but recommended. For high compression engines or engines with power adders like forced induction or nitrous, it’s highly recommended to re-torque the cylinder heads after the first heat cycle, wait a several hours to allow the engine to return to ambient temperature before re-torqueing.

The Edelbrock head gaskets work well with applications running pump gas. If the application is not running pump gas then select the appropriate head gasket for your compression ratio.

The Edelbrock head gasket for SBC does not offer the steam holes for the 400ci. engine. The Fel-Pro part number #1014 can be used for the 400 ci. engines.

Edelbrock recommends installing the exhaust gaskets dry.

Valve cover gaskets can be installed dry. Some engine builders like some sealer like Gasgacinch to hold the valve cover gasket in place on the valve cover, from the head to the valve cover gasket should be installed dry.

In some cases, the valve cover gaskets might not fit all the valve covers on the market. If the gasket is slightly to long, then use a straight edge with a razor blade and trim off the excess material.

The Edelbrock heat insulator gasket does not require any gaskets for installation, the heat insulator gaskets are made of gasket material.

Recommend using a thin amount of silicone on the water pump gaskets to ensure a good seal.

For street applications that have stock engines an Edelbrock Performer/Performer EPS intake manifold would be a great choice. Edelbrock Performer intakes also work well with applications that are running a mild camshaft. For modified engines running larger camshafts, it would be best to match up the intake manifold with the operating range of the camshaft your running or refer to cam card. Speak to the cam manufacturer if you need to find out the operating range of the cam. Edelbrock offers intake manifolds with matching camshafts to help eliminate the guess work.

Recommend using high temp silicone in place of the end seal as the silicone will give you a better seal. In many cases the end seal will be too thick or thin to seal properly with the aftermarket Edelbrock intake manifold. If the end seals are too thin, then they will not compress properly and leak. If the seals are too thick then you can run into a problem with warping the intake and potential vacuum leaks due to end seals holding the intake up and not allowing the intake gaskets to compress properly.

The reason you have a gap between the distributor and the intake manifold is due to the distributor drive not engaging into the oil pump drive. In some cases, you may have to use a long flat blade screw driver (or oil pump priming tool) and move the oil pump drive slightly to allow the distributor and oil pump drive to align and allow the distributor to drop all the way down.

It’s very common for the distributor hole in the intake manifold to be larger than the distributor. The hole itself does not locate the distributor. Once the distributor is engaged all the way down to the flat surface on the intake manifold it will locate itself.

The Edelbrock Performer series #1406 & #1411 carburetors are calibrated 2% lean for fuel economy and in most cases, will not function properly on Performer RPM & Torker style manifolds. Most people think you can just change the calibration of the carburetor and turn it into one of the Edelbrock performance carbs. This is not the case as the Venturi boosters are also different and Edelbrock does not sell Venturi boosters separately. In most cases when using one of our economy style carbs on a Performer RPM or Torker style intakes will cause hesitations and surging in the lower RPM range.

There are a few different circumstances that will cause the intake manifold bolt holes to sit higher than the intake bolt holes on the heads. One thing that is over looked in a lot of cases are dowels in the block/heads. The Edelbrock intakes do not have any provisions to work with dowels so they will need to be removed before intake can be installed properly. Be sure the intake clears the valve cover rails; some applications will require to put a 45° break at the top of the intake flange for valve cover rail break back clearance. If you are not running into these problems and your intake manifold is setting on the head sealing surface, then more than likely the deck of your heads or block have been machined. When the deck surface of the heads or block are machined, this will now put the intake bolt holes in the head lower and will cause intake manifold bolts to not line up properly. To solve this the intake manifold or intake head surface will need to be machined.

If any of the intake manifold bolts go into a water jacket or into the lifter valley oil galley, sealer should be used on those bolts. Would recommend using some silicone on the first couple threads of the intake manifold bolts before they are installed. If this is not done, then oil/coolant will ladder up the intake bolt threads and puddle on the intake manifold.

Some Edelbrock intake manifolds use special length intake bolts due to the intake manifold design. Others may require longer bolts due to the fact you must run 1/8” thick hardened washers with the aluminum intake manifolds so the aluminum does not gull and cause an incorrect torque reading.

Edelbrock intake manifolds do not come with intake manifold gaskets. do offer a line of intake gaskets sold separately that are designed to match most Edelbrock intake manifolds.

There are a couple steps to ensure you get your intake gaskets sealed up properly, below we will go over the steps.

• Coat head surface and cylinder head side of intake gaskets with 2 coats letting dry between coats with Edelbrock Gasgacinch #9300.
• Within a few minutes gaskets and surface will become tacky to the touch. Carefully place gaskets on head surface, aligning ports and bolt holes.
• With Gasket in place apply a small amount of RTV High Temp silicone sealer around water passages (intake manifold side only).
• With Edelbrock manifolds, you must use RTV High Temp silicone sealer instead of end seal gaskets. Apply a 1/4" thick ribbon of sealant across each end seal surface. Some installations will require 02 sensor safe silicone.

Edelbrock does NOT recommend using a carburetor lift plate to remove or installing an engine. The Edelbrock intake manifolds are made of aluminum and the 5/16” carb flange holes are not Heli-coiled.

Some Teflon tape or Paste needs to be installed on any of the NPT fittings that thread into the intake manifold. Use the Teflon tape/paste on the first couple threads of the NPT fitting before the fitting is installed.

Do not use a torque wrench on NPT fittings. Use some Teflon tape/paste on the first couple threads of the NPT fitting. Install fittings into the intake manifold hand tight, then with a couple fingers on a box end wrench lightly snug up fitting. Use caution when tightening up NPT fittings, they have tapered threads and if over tightened can crack the intake manifold.

Some Edelbrock intake manifolds require the use of a #2732 spacer.

Take a few pieces of clay, form them into cones and set them on your air cleaner. Then, gently close the hood all the way making sure you feel for obstructions. If an obstruction is felt stop so you do not cause damage. Re-open your hood to see compressed clay so you can measure it to check for hood clearance. If you don’t have clay handy you can do the same thing by balling up some foil balls.

If your stock engine uses a bypass to the intake manifold you should install it onto the Edelbrock intake also. If a bypass is not installed, you may have problems with the engine running hot.

The Edelbrock Air-Gap intake manifolds are not recommended for cold weather climates. In cold weather, the air/fuel charge is to cold, you will have problems with fuel puddling in the intake runners and will not perform properly. The RPM Air-Gap intakes work extremely well to keep the air/fuel charge cool in warm/hot weather and can give you performance gains over non Air-Gap intake manifolds.

Simple Green works well to clean up an Edelbrock intake manifold. For best results remove intake manifold from engine.

First, it’s very important to be sure all mating surfaces are clean. With water necks that use a gasket, coat both sides of the water neck gasket with silicone. Install the water neck and start to snug up the bolts when the silicone starts to squeeze out the sides of the water neck, stop, Let the silicone cure overnight and then finish tightening the water neck bolts.

If the NPT fittings are leaking going into the intake manifold, be sure Teflon tape/paste was used and be sure the boss the fitting threads into is not cracked. The NPT fitting is a tapered thread and can crack the intake manifold if over tightened.

The embossed bead on the intake gasket should face up towards the intake manifold.

The Edelbrock Dual-Quad intake manifolds (non-tunnel ram) are designed to work with Edelbrock style carburetors. With the carb pads located so close together other manufacturer carburetors will have interference problems.

In a lot of cases the intake manifold bolt torque specs will change from stock to an aftermarket Edelbrock aluminum intake manifold. Always refer to the installation instructions for torque specs. Instructions are also located in the Edelbrock Tech Center

If you have an end seal leak, the intake manifold will need to be removed, inspected, cleaned and reinstalled. The most common reasons for end seal leaks is due to the use of cork or rubber end seals. Edelbrock does not recommend the use of cork or rubber end seals, we recommend a ¼” bead of silicone to be used in place of the end seals. If silicone was used, then more than likely the surfaces were not cleaned properly. Be sure the block and manifold end seal surface is very clean, using lacquer thinner clean both surfaces. Be sure to let the silicone cure overnight before the engine is started to ensure the silicone has had time to cure and seal up. If your engine has an oil sending unit located on the end seal surface, be sure it’s not the oil sending unit leaking where it threads into the block thread sealant should be used on the oil sending unit.

If your engine will not start and only backfires, then this in more than likely an ignition problem or a large vacuum leak. If your distributor was removed to install the intake manifold, then you must be sure the distributor is installed correctly not 180° out. If your distributor is installed correct, then double check your firing order. Ignition would be the most common thing to cause the engine backfire, if everything checks out start double checking all your vacuum lines and connections. Be sure end seals were not used, this can allow the intake to not seal properly. Also, be sure all dowel pins were removed if engine is equipped with intake dowels. The Edelbrock intake manifolds do not have any provisions to receive dowel pins and if not removed will not allow intake to seal properly.

Sealer should have been used on the first few threads of the intake manifold bolts. Bolts that go into an oil galley/lifter valley or into a water jacket will require the use of sealer on the bolts threads. If not done the oil/coolant will ladder up the intake manifold bolt threads and pool up on the intake manifold.

One of the more common reasons an engine would run hot after an intake manifold installation is due to air in the cooling system. Get the front end of the vehicle up in the air using some wheel ramps. With the engine cold remove the radiator cap and start the engine for a couple minutes. Doing this will work the air pockets out of the cooling system. Be sure the thermostat was installed properly also. Things to also consider for a hot running engine. Be sure ignition timing is set correct and be sure the carburetor calibration is correct.

An easy way to plug the oil filler tube is to use a 1-1/4” freeze plug along with some Loctite, or RTV silicone.

If your PCV is sucking a lot of oil, then more than likely the PCV is not baffled. Remove the PCV valve, you should see a shield/baffle below the hole where the PCV is located. If there is no shield/baffle, then one will need to be installed to resolve this problem.

It’s very common for the intake manifold port to be smaller than the head intake ports entries. This helps keep the air velocity up and helps with throttle response. In racing applications, it’s common to port-match the manifold to match the cylinder head port entry or opening, for peak performance. In street applications, the only time port matching your intake manifold to the cylinder heads is recommended is if your operating range exceeds the manifolds range, or on large displacement engine combos.

Because of the valve cover break back on L-98 heads and the extra material on the Edelbrock RPM Air-Gap for port matching, it can be common to have an interference problem. To solve this a 45° break needs to machined at the top of the intake flange to allow for clearance.

The GM Fast burn heads have dual bolt patterns, one for Vortec pattern and one for 1986 and earlier bolt pattern intake manifolds. The standard Vortec design intake manifolds fit the GM Fast burn heads without a problem. Not the same case for the 1986 and earlier bolt pattern intakes, the conventional port location intakes can’t be used on fast burn heads. If you would like to use the 1986 and earlier intake manifold, it must be a high port design/raised runner design.

The Edelbrock break-in engine oil must be changed no more than 300 miles after break-in.

The Edelbrock break-in oil has an adequate amount of zinc in the oil for a flat tappet camshaft. There is no need to add any oil additives with Edelbrock break-in oil.

The Edelbrock engine oil supplement #1074 treats up to 6 quarts of conventional motor oil.

The Edelbrock engine oil supplement must be used with every oil change with a flat tappet camshaft unless the oil your running has zinc and is designed for flat tappet camshafts.

One way to ensure the A/B epoxy will stay in place is to root the epoxy. Before applying the epoxy to the intake manifold drill some small holes in the area the epoxy is being used. Push the epoxy into the holes, this will root the epoxy to help keep it in place.

The Edelbrock high temp silicone sealant is sensor safe.

Recommend using high temp RTV in place of the end seal, the RTV will give you a better seal. In many cases the end seal will be too thick or thin to seal properly with the aftermarket Edelbrock intake manifold. If the end seals are too thin then they will not compress properly and leak. If the seals are too thick then you can run into a problem with warping the intake and potential vacuum leaks due to end seals holding the intake up and not allowing intake gaskets to compress properly.