i tried searching for specific info on what year diff. to get and i didnt get any specific answers. basically the 10 bolt posi in my 86 iroc gave out. no more posi, just peg leggers from here on out. anyways i here a good upgrade is a 4th gen rear other than the fact that itll stick out about an inch more on each side. so basically im asking. my iroc has 4 wheel discs so i wont have to swap out the proportioning valve, but what years came with a good gear ratio and disc brakes? also is it a straight forward swap? hook up the brake lines, attach driveshaft and all the other suspension stuff or will the brake lines need anything special. thanks

 

I dont know everything but here's what I do know. Feel free to correct me if I'm wrong.

1. Other than the axle width difference, 4th gen rears are exactly the same as 3rd gen ones aside from brakes. 98-02 models have a Zexel-Torsen posi which is nice for road racing/autoX. Their e-brake setup is different and will require some fab work.

2. 4th gen rears stick out 2 inches farther on each side. In my opinion it's noticable and looks bad with stock wheels. Some guys like it. To each his own.

3. I am not positive, but I think your 3rd gen brakes will swap right over to LT1-style disc rears. But there'd be no point. You might as well just use those.

4. Gear ratio depends on a lot of things. Manual cars got 3.42's usually, though. Try to find a rear from a manual car.

5. Everything bolts up about the same. No crazy fab work needed. The worst thing will be figuring out a way to get a functioning e-brake with the 98-02 rears. Other than that it's pretty much bolt-in.

 

You may find some of the info in the following link useful (check the info on proportioning valves):

https://www.thirdgen.org/forums/tran...-10-bolts.html

Check the link there on "What 10-Bolt Will Swap into My Car?"

Oh, and Ed Miller now makes direct-fit cables for the LS1 swap:

http://www.flynbye.com/catalog/i153.html

JamesC

 

Wow, that's sweet that Ed finally got the conversion cables up for sale! I've had a complete set of LS1 rear brakes sitting in the garage for about a year now, but I've held off on putting them on due to the headache of adapting the e-brake cables.