[mgarblik]

Glad you are up and running. Couple things to consider. First timing. I would verify TDC is TDC with a piston stop or at the very least a camera to look at the piston and the timing marks. That should get you close. I hate to pick on an engine builder I don't know, but a Pontiac V-8, especially with closed chamber heads won't run it's best at 2-3 degrees retarded timing. The combustion chambers are so inefficient, your fuel mileage and performance will suffer. I can't imagine this engine running well without at least 6-8 degrees advance at idle. To be safe, and avoid detonation, borrow or buy a dial back style timing light. Check your total timing @ 4000-4500 RPM. I think you would be plenty safe at 32-34 degrees. Then see what your initial timing is at idle, vacuum disconnected. Then see what your timing is with the vacuum attached. With todays lousy fuel, you may find the vacuum canister is adding 20-22 degrees of timing at high vacuum. That is where your detonation may be happening. On almost all rebuilds with old distributors, I have to mechanically limit the vacuum advance to 10-12 degrees to avoid detonation on lousy pump gas. This can be done by welding in a stop, installing a screw, or possibly sliding a small diameter sleeve over the post on the vacuum unit.

Getting your distributor and timing straightened out first will likely eliminate your "carburetor" problems. Get the ignition right first, then mess with the carburetor if needed. Good luck with it.