Had about 15 nice 67 to 72 Chev and GM trucks here for 25 years (all SB and BB V8s) - still have several - and have fought serious ethanol problems. Foolish enough to try to do it all myself.
The Qjets always seem the best fit for these engines and they run out really well - power and mileage - if kept clean and adjusted. I recommend staying with it and, as others mentioned, correct CFM for engine is important, especially if someone has gone to a later model carb.
Three of these trucks, two of which had aftermarket intakes when I got them (one a 350, one a 383 stroker, and one a 402 BB) came with the Edelbrock version of the Carter AFB. I have found those to be very dependable and a lot easier to clean/rebuild than the Qjet, although correct fuel pump pressure seems more of an issue with these. The 402 BB with the AFB type powered a 72 C30 mororhome and we drove it 85k miles all over the US in 18 years. I never had to open that carb,
Best wishes have fun with it.
