how do i adjust fuel/air mixture on 5.0litre 302?

Question

i have a beefed up 302 and it is setup for N20 the has an aftermarket cam, gt40 heads victor jr intake, bbk cold air induction and 3:73 gear. When i slowly ease through first gear and slightly get down in second it seems like the car bogges down and slowly picks up after about the 3300rpm stage. What could be the problem?

the engine is also fuel injected i forgot to add that need 2 know info.

the engine is also fuel injected i forgot to add that need 2 know info.

Answer 1

Is it carbed (79-86) or fuel injection (87-93)? Try opening/closing the air intake.

Answer 2

A victor Jr. has an open plenum and does not work well on the street as it's designed for an RPM range from 2,500 - 6,000 rpm. I'm betting you also have a double pumper Holley which adds to the problem. Holley now makes a beautiful 650 CFM carburetor with vacuum secondaries. On the street you need lots of off-idol velocity which a smaller carburetor would create. If you were to switch back to a Weiand # 8020 Stealth divided intake complete with an air-gap and the smaller Holley with vacuum secondaries I'd honestly guaranty your problems would be over.

For now try a more radical plastic accelerator pump cam on the left side of the primary throttle shaft. If that doesn't make it a larger diameter accelerator pump booster nozzles to try to cover up the bog. Last but not least try a 50 cc accelerator pump on the primary side of the carburetor.

To adjust a Holley first set the timing. Hook up a well dampened vacuum gage anywhere below the throttle plates. Very slowly turn one idol screw (one at a time) on the side of the float bowl clockwise until the vacuum begins to drop. Slowly turn the idol screw counter clockwise till the vacuum reaches the highest value. Repeat on the other side. If you have an electric tachometer so much the better. You can use this if you don't have a vacuum guage.

This type of an adjustment will not solve light throttle tip-ins. Remove both of the float chambers and check to see what the number stamping is on each of the power valves which are screwed in the back side (opposite side of the jets) of the main and secondary metering bodies. The numbers will be for instance 5, 5.5, 6, 6.5, 7, 7.5. 8, 8.5, 9. 9.5, 10, 10.5. The power valves add fuel in the main curcuits as the vacuum drops in the intake manifold as you press on the accelerator. You need to know exactly what the intake manifold vacuum is at idol befor making a power valve change. Select a new powervalve for both metering bodies which have a number stamping that is at least 2 numbers higher than the idol vacuum. The object of this is: The power valves will supply a small added amount of fuel to the booster rings inside the carbuerator venturies to help with the bog your experiancing. Be sure that your choice of power valves is the same on the primary and secondary metering bodies.