Jerry - Carter produced millions of Q-Jets under license from GM from 1966 to the late 1970's. The Q-Jet was (and is) one of the finest street carburetors ever built at any price. There were some "teething" problems in the early years, but by 1968, this was a fine carburetor.
As to the replacement carbs for the Chevy 6, if I drove a 6 cylinder Chevy, it would have a Carter. Both the Carter W-1 which was replaced by the Rochester B and the newer Carter YF are superior to the Rochester B. Of course, if the car is a "showcar", one is stuck with the original carb.
Jon.
