I have an ‘88 5.7 TPI IROC, I did a T5 swap many years ago.

I have a T56 I bought 5 years ago, and due to my late wife’s illness, it’s been sitting in storage for nearly 4 years now.

Part of the delay was the IROC has a 2.77 rear someone swapped in..even though my car was originally built as a 4 wheel disc car, it currently has rear drums…but I noted that they never bothered swapping out the 4-wheel disc proportioning valve…which explains some of the odd braking issues with my car.

I’ve found a 3.73 posi disc 10-bolt from an ‘84 Firebird, and that sounds like it would be perfect for my ‘88.

So…what will I need for the swap? I’m assuming my driveshaft is a simple bolt-in, but my big question is the emergency brake cable. I’m assuming, since it’s missing from the 3.73, I’m going to need to find an emergency brake cable…unless the cable I have on the Borg-Warner disc rear end I have lying around is the correct one…

What will I need to find to install this rear properly in my ‘88?

 

 

Well, good news/bad news….I got the axle. Ring gear shows P/N 22521257, 41/11, so it is a 3.73…but it looks like the posi traction is toast.

From what I’ve gathered, the parts are no longer available to rebuild the posi, so looks like I’m going to be shopping for one.

Ring gear and pinion are in very nice shape, and the previous owner had the bearings replaced about 20,000 miles ago.

Any recommendations on what posi unit to buy?

 

I'm not up on them, only that I see after-market prices are ridiculous. Almost $500 or more. I hear alot about Eaton, as a popular brand. For the life of me, I can't remember the brand that was available thru the aftermarket, in the 70s, and 80s. Driving me crazy. It wasn't Eaton. I have a 12 bolt one buried in my garage. Anyone?

I just remembered the popular brand of posi's in the aftermarket of the past. It was Moroso, and their "brute Strength" differential carrier. I see Summit had a listing, but it was "unavailable", (as usual these days). Not sure if they had one for the 3rd gen rears, but they had a good reputation. And it wouldn't surprise me if Eaton was the original manufacturer. They've been around a while.