quote: "and edelbrock performer carb, 500 cfm"
Problem solved. No flaming intended at all but that has got to be the worst carb. ever created....well maybe not the worst.
I had a '79 CJ w/304 V8 (Edel Perf. 500cfm) and a '83 Z28 350ci (Edel. Perf. 750cfm). I tried and tried and tried and tried to get that carb to run correctly on either rig and never got it down, even with help from several people. I gave up on them and switched to a quadra-jet and life was good after that. I just couldn't believe how much better they ran. I took the Edel carb out and shot it with my 50 gauge muzzle loader....several times.
Mechanical secondaries on that carb correct? ....hmm...might check the vacuum advance for the dist to see if you have a pinhole leak.