Rebuilding an 85 cutlass, and am looking to replace the rearend. The car came with a 78' 7.5" 2.29 ratio non posi. Found an 82 Z28 at the local junkyard, pretty sure those came with posi 3.73 rearends. Anyone know if the Z28 rearend will fit in my cutlass. The way the Z28 is sitting I cant really get underneath it to measure. The same junkyard has about 3 mid 80's chevy S10's, I thought some of those had posi with 3.73 ratio. Any help in my quest for a better rearend would be greatly appreciated.

 

No the Camaro rear end won't work. Neither will the S-10 rear end, but the gears and carrier out of those rear ends will work in yours. Most S-10's with 4.3's had 3.42 gears and ones with 2.8's had 3.73.

If you want a better stock rear end that will bolt in your car. Then you want a 8.5 out of a G-body 442, Monte Carlo SS, or Grand National.

 

A 71-72 A-body 8.5" rear will work too but Andy's suggestion is the easiest route. The 71-72 route will need some aftermarket adjustable upper control arms and a few mods but it fits.

 

Thanks guys, I may have a lead on a monte carlo rearend just afraid the guy wants more than its worth.