Needing a new (and improved) 8.5" 10-bolt rear posi clutch pack?

[69hurstolds]

Several years ago Bruce Ponti had a bunch of correct, square-eared posi-traction plates and frictions made for the 10 bolt corporate 8.5" GM rear end with carriers 410408/410409 (S- spring only) because the GM supply had all but dried up. They're believed to be a bit more of an upgrade from the original GM stuff in that they're a tad thicker than stock. They replace the GM p/n 231127. And unlike the GM stuff, they come with a shim pack as well, and free advice on any questions. Note: These do not fit the Eaton carriers, the ones with the little coil springs.

I think a couple of rear end companies were selling some sets for a while, but they quit doing parts sales because they made more by selling complete rebuilt carriers. Are these any better or worse than the round ear versions? I dunno.

When they were first available, I felt I wasn't going to rebuild the rear end in the 85 442. So I didn't buy a set then. But crossing fingers without much hope, I did end up emailing him recently and was surprised that he still happens to have some sets left. So if you need a new posi clutch pack for your car, he probably can help you out. Just toss him an email. I have no dog in this hunt other than buying a set myself. Just passing this along.

Contact:
[email protected]

Website to see more pictures and descriptions (keep in mind, this is an OLD OLD posting)
1970 Buick 455 PCV Hose (buickperformanceclub.com)

 

[Hotboyrn84]

Are all three used as shims for the clutch unit? The shims that looked like came with the new shim kits all looked like the flat circle shim pictured. Do the other two install the same, like seat the same if they are shims. Sorry if the questions are dumb. I just bought a 8.5 out of a 87 GN for my 80 cutlass and have started looking at options if I don't like the 3.73 already in it supposedly.

 

[69hurstolds]

If it's out of a GN, and stock, it's a 3.42.

Not sure what you're getting at with the shim, but you need to shim the clutch packs to ensure it's tight enough to maintain .001"-.006" pinion to side gear backlash when compressed. This is done by following the CSM where you put a screwdriver in between the side gear and cross shaft with a dial indicator set up to check pinion backlash. Doing one side, then the other. It's rather lengthy process to get there and explain it simply here, but you're wanting to ensure the spring will compress the clutch packs and still maintain the proper side gear spacing to maintain the .001"-.006" backlash on the pinion gears to side gears.