I just got off the phone with David at "isuzuswapper" he just told me that up till 85 4bd1 (b4 they were turbo) engines came with chevy transmissions and they were "SAE" housings. In 85 they change to Japanesse automatic tranmissions and these took different flywheel housings. So, if you can find an older 4bd1 engine you can get a ring and bolt up what ever domestic tranny you like.
Dieseltim