4 Barrel Quadrajet Air/Fuel Adjustment

[mntoy]

I reciently dipped my quadrajets carb, had the bushings replaced and rebuilt the carb. I am unable to adjust the idle down low enough. I can adjust it at cold start but when I drive the truck a 1973 C20 with a 350 and th400 for any lenght of time the idle seems to speed up alot. My question is do the two air/fuel screws (front drivers and passanger side screws) affect the idle too? if so is one air and one fuel or are the both air/fuel for each of the primaries? secondly which way is richer (more fuel) and which way is leaner (more air) screw in or screw out? Any help would be greatly appriecated. Thanks in advance.