Jon I was scratching my head on that as well. Chevrolet used the Rochester B (not BC obviously) on trucks in 1959 (attached).
Brain spasm here: I was thinking 1960 was the transition for truck to the low-profile Rochester B [my guess to have same carburetor as cars (standard transmission) for reduced inventory]. Chevrolet would have to use up their inventory of existing carburetors...1959? 1960-62 Carter decides to do the same but not make a low profile carburetor, like the YF 3211S, with manual choke. That would allow Carter's existing inventory of YF 2100S to be used up. Just a guess.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
