Hi Tim, My Chevy parts book shows the 41 to 54 pass. using the same internal shaft in the tube and the same carrier housing. It shows the 48 to 54 1/2 ton using a 7/8" longer internal shaft and a different carrier housing than the car. Might be usable if you use the whole assembly but your tires might move forward in the wheel opening by 7/8". The 3:55 will give you better crusing speed but either rear end should work with the trans.
Gael
