Edelbrock Air Gap on Magnum 318 Problems

A few things to try:

1. Make sure squirter lever is adjusted right (the screw with a spring that rides the lever on the other side of the pump cam).

2. Get a pump cam assortment and try a few different ones. If its a lean stumble, it should get fixed by getting more pump shot early. Also, make sure your squirters are delivering a nice hard stream of fuel. If they are just letting fuel dribble out, its time for a rebuild (the diaphrams are cheap and easy to replace).

3. Lastly....Another thing to try would be locking your timing out @ 32 (I think that was what you said your max was). This helped my street/strip car years ago with a off idle stumble that I could not get rid of...but if you are mostly street you might not want to go this route.