Isn't the 261-sized "B" a pretty unique critter?
Yes, "unique" to the 261 engine
The 261 Rochester B had a larger venturi throat inner diameter and a larger throttle body inner diameter (compared to the 235 Rochester B).
It looks like 1958-1963 261 carb specs were the same but the air cleaner attachment might have changed in 1960?
Maybe someone knows when the air cleaner attachment changed?
The 1954-1959 261 Rochester carb model number was 7005140
The 1960-1963 261 Rochester carb model number was 7015143
