Well, I have to say that I am surprised. This is supposed to be the premier forum for QJ's, yet not a single response. I assume that is because I'm out there in the grey area, where few have gone before. That is understandable.
After re reading Cliff's book, I am understanding the relationship between bleeds and fuel flow. I was hoping that a more experience QJ guy would come on and say, 'yes, I'd start with such and such size main and idle bleeds.' But no. So, I found that with a 231 v6 turbo QJ, the bleeds were around .050 with 67 main jets. For a trans am with a 301, the bleeds were about .065 with .072 main jets. I believe I will begin there. The 301 spins faster, whereas the 300 I6 tops at 4500 rpm, but the engine is working harder, pushing more weight with a truck body, so, I'm thinking the larger mains may be needed.
Note to help others:After reading Cliff's book several times I was still confused regarding the Upper idle air bleed and the main air bleed in the air horn. Photos showing either one are on different pages and should be side by side. The air bleeds seemed one and the same to me. Then I noted, if the orifice is right beside the air horn screw it is the main air bleed. If, however, the orifice is not on the little nub or mound beside the screw hole, but closer to the vertical choke flap 'wall', then it is the upper idle air bleed.