Yes the fuel is going to percolate in a Carter style carb.

Is your crossover still open, block it, switch to an Alum intake AND the Holley carb , though an 850 is a little big unless you are running an 800 ebrock , I hope you don't have the POS performer 750 , if so drop in it the bottom of the everglades.


My friend has a 383 I did for him last year , runs what I outline above with the cheapest , crappiest, gas he can afford and no issues.