gumbyssfakee

I got these numbers off of my axel H2B 351. Stamped on the housing I saw the letter "A" and what was either a "N" or "Z". The car is 71 Cutlass 4dr. Any help on identifying this rear in terms of gears and if its correct for this car plus other helpful info would be appreciated.

monzaz

Well being a 1971 cutlass...It will most likely be a 8.5 10 bolt rear diff and have bolt in axles with 28 spline axles.

Check the pictures and see if the rear cover looks like the one below ...

gumbyssfakee

I'm fairly confident that it is a 28 spline and know that its a 10 bolt but my real problem is the 8.5 part. A few guys have put the idea in my head that it could possibly be an 8.2 instead of the 8.5. Currently I have an open diff and want a posi so I am trying to figure out what i have. Im hoping the casting # will help.

wmachine

The 8.2 would be the earlier "B" and "P" 10-bolt rear from pre-'68.
Does your cover look like what monzaz posted? He's our differential guru, and what he tells you can be taken to the bank.

monzaz

Can you post pictures of your diff??? If so we will ID the rear for you.

Does the yoke use u-bolts and nuts to hold the u-joint to the yoke on the rear? OR does it use 2 straps and 4 screw in bolts to hold the u-joint in place?

gumbyssfakee

thanks. ill get some pictures up saturday morning.

monzaz

sTILL HERE....LOL. Just kidding take your time. Jim

gumbyssfakee

yea im still here i'm trying to get some time on a lift so i can take a few good clear pictures.

monzaz

The parts I need to see you will not even need to do that ....But if it makes it easier for you... then will wait. Jim