The 37-40 (and some 41 applications) mounts have a 10” spacing between the two holes. The 42-48 closed drive rear mounts have a 8” spacing. Both can be bolted up to any 32-48 case (top or side load). The 42-52 pickup truck rear mounts were open driveline but still have the 8” spacing. Those also bolt up to all the 32-48 cases.