we are swaping a 4th gen rear end into a 1991 gta, but we cannot find some info, we have found info that says we need to install a adjustable proportioning valve, but we are not sure. We have two rear ends on out of a 94 z28 and one out of a 01 z28. We wanted to know what one would be better and all what we would need, ive been told that they are direct bolt on swaps no mods needed, but i have also been told that you need to do all kinds of crap to make it work, please help asap, thanks..

 

When I put a 95 Z-28 Rear in mine, everything bolted up exactly as the 3rdgen rear did with the exception or the E-brake cable. I had to modify the bracket somewhat but couldnt even begin to describe how to do it. Its one of those things you will see when laying under the car. I used the stock Pro-valve (disc/drum) and it worked fine.

 

The only thing different in those rears is that they could have 2.73, 3.23, or 3.42 gears in them. Also, that LS1 rear could have the Auburn unit in it if it came out of an SLP car.

 

yeah i put a rear out of a 94 z28 and it fit with no probs...one thing you need to keep in mind is the axle tubes are longer than the 3rd gen rears so your wheels will stick out. I even used disc brakes from that same year on there, I bought an adjustable proportioning valve and they work great. The only thing i still havent figured out is the parking brake conversion.

 

The 01 should have larger rear discs (I think), so you might look into using that one. Im using the stock valve, too, and it works decent, but I'll go to an adjustable one once i have a garage to work in again. Those LS1 brakes are huge, its kinda weird having the same size front/rear discs lol.