I believe the blocks are all the same bolt pattern concern. Bellhousings are different depending on application. trucks are different than cars, fluid drives are diffeent that dry clutch. Also crankshafts are different. Some are 4 bolt typically plymouth w/o fluid drive, dodges have 8 bolts, for the heavier fluid drive assembly, I have one with a 6 bolt (later 230 plymouth) That about does it for the short block engines (210, 218, 230 ) The long block cars Chrysler, Desoto, and Canadian manufacture may have some different permutations but the bell housings are interchangable.
Pre 35 the position of the starter was different as the engine block casting were different. So thee might be some differnces n the bell housing to reflect this change.