Regarding the front drum to support bushing - there are two reaction shaft support bushing sizes from 1962 - 2008, narrow and wide. The metal seal ring spacing never changed on the wide bushing support.
I think you can install the wide bushing drum on a narrow bushing support and the unit will assemble
The ring spacing did change to compensate for the wider bushing. Narrow bushing drum will fit on wide bushing support but ring location will be wrong. Wide bushing drum won't physically fit on narrow bushing support.
