I guess I didn't know the 216's used Rochester carburetors, I thought they all were Carter W-1's.
Joe - not certain exactly when Chevrolet discontinued the 216, but at least in 1951 there was a 216 that used Rochester type B carbs.
However, GM instructed Chevrolet dealers to replace earlier superior (opinion) Carter W-1's with the inferior (opinion) Rochester B as a service replacement.
Jon.