Thread: dual quads

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Edelbrocks have vacuum-operated secondaries, so the secondaries will not operate until there is enough manifold vacuum to open them. Therefore, you cannot over-carburet the motor, even with 2-4 barrels. Most fellows will rig up the throttle linkage so that the motor runs on the primary 2 barrels of the rear carb, then at about 1/2 throttle, the primary 2 barrels of the front carb will chime in. Then, if there is enough manifold vacuum to operate the secondaries of each carb, they will open. The resultant sound is one you will never forget....BA-WAAAAAAAAAAAAA......

Be sure you use enough air filter so you don't choke the motor down.

If I just wanted the LOOK of two 4-bbls, and weren't interested in making max hp, I would probably use an Edelbrock C26 manifold, part number 5425, and top it with an 1803 and an 1804 carburetor, 500 CFM each.

If I wanted additional performance from the motor, as well as looks, I would use the RPM manifold, part number 7525, along with the 1803 and 1804 carbs. The added height of the RPM makes it the best bet for street hp. You may encounter some driveability issues in cold weather with the Air Gap feature of this manifold. Street motors need the heat of the motor to help atomize the fuel/air mixture for a good, clean burn. I thought Edelbrock made a 2-4 RPM intake that was a closed design, not the Air Gap, but I cannot find it now. Maybe they stopped making it. There is insufficient room to use an HEI distributor with the 7525, so you would have to use a smaller diameter distributor body.

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