Buyig a 4spd trans

A body Has 4.35 dia. bearing retainer, a short tail shaft, and the shifter mounts in the middle of it.
B body only has 4. 8 dia. bearing retainer and the shifter lug at the front of the tailshaft.
70 up B & E body trans has 4.8 bearing retainer and shifter lugs front and back of tailshaft.
OD trans has 5.100 bearing retainer. And would have been in A bodies, trucks, or vans.
Here's what you are looking for if you want to use an E body, van, or a truck trans. The truck and vans need the rear lugs drilled and tapped to work.
http://www.bigblockdart.com/techpages/abconv.shtml

Here are the pics and info on the differences. :headbang:
http://www.bigblockdart.com/techpages/4sptech.shtml