hey guys whats up, ive got a quick question, a friend of mine has a 91 RS and he bought a posi for a 7.5" 10 bolt from another guy i know, he tried to put it in but said he couldnt get it to fit, now heres the question: He has 3.08 gears and i have 3.23 now i am aware that they have different carriers for 3.08 and numerically lower and a different one for 3.23 and up, now this particular one for a 3.23 so now i inheret it. So is the reason that it didnt fit his car because of the different carrier sizes? or is it the wrong posi? also what gear ratio would you recommend for my car (86 IROC-Z with a mildly modded 305 i.e. cam, exhaust) Also how hard is it to do a gear/carrier swap? Thanks for the input!

Humm, nobody replied...

7.5" came in 2- and 3-series carries, as you stated. Also came in 26 and 28 axle spline versions. That may have been his problem. 10-bolts also came in 7-5/8", but the parts typically swap between 7-1/2" and 7-5/8" carriers/gears/housings.

Assuming you have an automatic tranny, 3.23 and 3.42 are good compromise/dual-use ratios.

Installing gears is typically considered a job for those with proper equipment (about $300-worth of specialized tools) and experience/training. Typical prices quoted for labor range from $150-$300. If not done properly, excessive noise and premature wear are the results.

So let me get this straight. 92RS 305TBI........7.5???? or 7.62????
28Spline????? or 27 Spline????? 2.73 to 3.42 swap no problem??? Dont have to change carriers???

- 86 Iroc could have a 9 bolt rear, 10 bolt rear parts are not interchangeable.

- 92 RS is a 28 spline (axle), 27 spline (pinion), 7.625 ring gear.

- 2.73 and 3.42 use different carriers, but you can get a special 3.42 gear that will mount to a 2.73 carrier.

FINALLY!! Thanks a lot 88!! Now I can continue on with the purchases and installation. Appreciate it...........:hail: