I might be able to get my hands on a fourth gen posi rear end complete with the disk brakes. Will the rear end adapt over to my third generation? If it helps my car is a 91 and the rear-end is a 97. Plus does anybody have any idea on the horsepower gain?
91 TBI automatic, 2.73
97 V6 3.8 3.23 posi or 3.42 posi
Thanks for any help!!

 

There's no difference internally between your 91 and the 97 except that the 97 is about 2" longer on each side. This means you need some different backspace rims or your factory rims will stick out.

The fourth gen diff will bolt right up to the third gen suspension.

 

Thanks, I figured that the suspension would hook up ok, but I just wanted to make sure beforehand. That looks like a pretty nice car you got there too! Thanks again