Two different 833 manual trannys for an a body

The gear sets are interchangeable, set for set.
Either box can be converted either way, and/or to Slip-yoke. You just need a matching Tail and Mainshaft.
Personally, I prefer the longtail in my 68 Barracuda, with the shifter relocated to the rear, to between the buckets. And I prefer the slipyoke, only because it is convenient.