A833 overdrive V8 bellhousing?

The 833OD bellhousing has a 5.125" register because the input bearing retainer on an 833OD transmission has a 5.125" diameter. The regular 833's are either 4.3" or 4.8", all the A-body 833's had a 4.3" retainer.

The bellhousing you're looking for has casting #3743859, it came on 75-76 A bodies, 1975-80 F bodies, and 76-80 light trucks. This what you need, you'll just have to find one
Brewer's Performance - Mopar A833 4-Speed Transmission and Component Specialists

As for other differences, all the linkage is different. Z-bar, clutch linkage, etc will all have to be changed.