I have a 1970 Chevelle Malibu, was wondering how do I determine the size of the rearend. I see 8.2, 8.5, 10.5, and dont know how to determine the difference. It is a 10 bolt rearend, and I am going with 4.11 and a detroit locker

if it's the stock rearend 99% that it's an 8.2

I would post in the Transmission and Driveline Forum. You will get great answers there. I believe you will need to use a 12 bolt, 3 series carrier for 4.11 gears though.

Chuck

Measure the diameter of the ring gear, it should be 8.2". You will also need a four series carrier. Unless you are doing alot of drag racing I recommend a Eaton posi over a detroit locker, the detroit lockers make alot of rear end noise around turns.