I just aquired a new rear from a buddy, and all I know is it is a 10 bolt posi, old style (pre PBR) rear disc. It has 3.42 gears also. I need to install new races for the center bearings, along with a new spacer that goes between the race and axle tube. Can anyone be of help?

 

The races and bearing are the same for any 10 bolt from like 81 on up, so if your rear is originaly from a third gen there should be no questions as to what races are in there. Just call up a napa or something, and tell them you need carrier races for a 87 GTA, or a 91 B4C RS, or a 84 Crossfire Z28, it's all the same. And it doesn't matter disc or drum, sobe creative. Really impress the guy behind the counter by telling him you have a 92 Z28, 350 TPI with 4 wheel discs and a G92 rear. It's all the same. Just don't tell them you have the borg warner rear, then you'll get te wrong ****.

 

I wish it were that easy. I work at NAPA, and our computer and books both state it could be a 7.5, 7.685, 7.75, or an 8.5. I highly doubt its an 8.5, and I'm pretty sure the 7.685 belongs to the 9 bolt, but is it 7.5 or 7.75???

 

if it's the smaller 10 bolt it's 7.5/7.62. gm just wanted to confuse us all a bit by using two designations for the same piece. the other 10 bolt from mid 70s and earlier is 8.whatever. the "spacers" (actually shims) are matched to your rear and the size never changes and should never be changed. be real careful setting it up if you're missing the shims.

 

Let me quote myself to clarify what I meant. "If the rear end origianally came from a third gen, then there should be no question about races" Last time I checked, third gens did not come with 7.75 or 8.5 10 bolts. They only came with 7.5 and 7.625 10 bolts. These two rears both use the same bearings and races. So to sum this all up, if your rear end originally came from a third gen, you can give your local NAPA guy any third gen application, EXCEPT 9 BOLT REARS, and you will recieve the right stuff.