If you find an OD trans make sure it is as complete as possible.
Yes, some of the components from other MFG's will fit but there are some differences. The solenoids from the later Saganaw/BW OD's have a smaller diameter opening where it mounts to the unit. You can get a Ford, Rambler, or other's govenor but the drive gear will be different. Many of the internal components are the same such as the planetary set and the roller clutch but you cannot take the OD housing from another MFG and bolt it onto a Chevy trans.
Fred