Try turning you distributer while engine off. Don't loose any thing justice sure it spins a tiny bit. Then start her and look at the vac ad . vac advance is a lil diaphram you see on the distributed with a metal line on it runin to the carb base

Check to see it the dist spins when you increase throttle ( the dizz should advance as the throttle increases and the vacuum from the carb is supposed to turn that dist. If you rev it and your whole distributed doesn't turn that 1/16 or 1/8 .

I'm no expert by any means so don't take my word. I'm having problems with a new manifold and I'm always trying to pry the minds here with anwsers to questions I may have. They say start with the simplest conclusion and use our powers of deduction to determine what's wrong.

I think if you can determine that first the vac ad works then pull then carb to inspect then it would be a vac leak (windshield wiper open, cracked manifold )

Good luck man. Anybody else wanna chime in