Help identifying 4 speed transmissions

They are interchangeable after some point in the 1969 model year.

Before that, the B-body 4-speed only had one shifter mounting point.

Be sure to match the front bearing retainer to your bell though, the big block manual transmissions use the larger bearing retainer.

If yours all happen to have the small retainer, Brewers sells an adapter ring to get to the larger size.

If you want to try to see if any of the transmissions match a car that still exists, you can list them at Engine and Trans Lost & Found