Hello,
I am somewhat new to qjets, but have rebuilt a 7042264 (Pontiac) and a 7043252 (Olds) with Cliff's kit, bushings, and Recipe #1. The Pont carb is running great on a stock 400 Ponitac with 74 primaries & 41 rods.
I prefer to run the Olds carb due to the electric choke conversion, but cannot quite get it working as well as the Pont Carb. The Olds carb just seems to be a little flat, even the engine idle sounds "flat", although it idles fine. I can go through the gears just fine and run up to 5K, but not as responsive or strong as the Pontiac carb. If I did not have a better running carb to compare, I would have accepted it as normal.
I have tried primary jets from 70 up to 76, but settled on 73 (any larger causes stumble). I originally had leaking fuel around the accel pump area, found my airhorn to be a little warped, and ran a belt sander on it and used the thicker gasket (no longer leaks, at least not externally). The carb almost feels rich, but I think is still a little lean due to some backfire when engine braking.
Not sure what to try next, any suggestions?
