The pre-216 engines are about 2 inches longer, and there are several other differences. They also have poured Babbit main bearings, different size and length connecting rods, and a bunch of other differences. I believe the 216 was first used in either 1936 or 37, so anything older will not be a good candidate for that swap.
This one is supposed to be a 1930 engine- - - -not sure about the size. By 1933 they were using downdraft carbs.
http://www.oldride.com/parts/subsetmr/81015095039700.jpgJerry