'71 has the 8.2 in it.randys ring and pinion will
sell me a eaton unit and 4.11 gears and master kit for 600.00 to my door.have to do it during the weekend.i want to make sure i get the right eaton unit.how many splines are my axles.stock rear never touched 2.73's.some say 27 spline others say 28,would like to actually find someone that knows.did they have two different axles?i figure they mass produce them and would make just one axle.or is there some top secret way without pulling axles?
thanx guys,
shane

pull the axles and count the splines on the end of the axles that way you will know for sure also look at the bolts on the ring gear and see what size heads they have on them to see if its a 8.2 or 8.5 .8.2 has 9/16s head and 8.5 hase 5/8s heads .

If your axles are stock, you might want to replace them as well. Pull the axles to see how worn they are.

Originally posted by ehjorten:
If your axles are stock, you might want to replace them as well. Pull the axles to see how worn they are. Heck, you are getting into the 12 bolt $$ range right now anyway. Scour ebay. YOu can get a 12 bolt posi for 6-1200.

Figure 600 for the gears and carrier for the 8.2,
2-300 for axles, there is 8-900, then labor to put em in.......

Go 12

three reply's and not one person answered one question?i dont need a 12 bolt an 8.2 built nicely will do just fine for what i want.dont need axles im not putting 600 to the ground.i just want to know if anybody knows if gm put something other than an 8.2 rear in a plain jane 71 with 307 and th350 and how many splines
thanx
shane

[QUOTE]Originally posted by ovelle:
[QB] dont need axles im not putting 600 to the ground.

I think what Erik was saying, If the chase on the axle is worn, 10 bolt, 12 bolt, 28, 32 or 77 spline you will need to replace them.
JMOP Bob J.