any 6 pak gurus out there?

hoping someone can help me tune this gd sixpack. I have a 72 340 duster 340 plus 30.. comp cams 274h cam. here is where it gets interesting . the motor has 12.5 slugs . in trying to reduce the comp ratio it has cometic head gaskets .083. thick and a set of open chambered 318 heads with 188/160 valves. I cant remember what the cr actually is ? ANYWAY THE SIX PAK IS BRAND NEW.the only changes made were minimal. the center jets were changes out from 62s to 63s. the motor runs 8 in vacuum. and it has a 4.5 power valve. I have the initial timing at pretty much where it wants and @3000 36 degrees. the outboard carb idle screws are 1/8 out. I can get it to idle but clearly can tell it is rich. can anyone offer me a place to start. ? I really want to run the sixpak but in all honesty it ran great with a holley 770 street avenger and an ld340 intake.. beyond frustrated.please help?