I am not as familiar with what CCC setups the 4.3s had, but generally each engine family had its own unique CCC setup. Buick 231s had one setup, Chevy 305s had a different setup, and Olds 307s had yet another setup. Also Qjets and Dualjets are very application specific carbs, and a Buick Djet maybe setup too small for a 4.3 Chevy. I know with Qjets, Chevy ones used much larger air bleeds than BOP Qjets. I do know that later 4.3s used in MCLSs had TBI instead of carbs.