My 89 Formula 305TPI auto has the stock 2.73 rearend in it but has alot of road noise. I'm so sick of hearing it and I know it cant be good for the good fo rthe car. A buddy of mine has I think a 8 6 V6 Camaro that has a T-5 Tranny and a 3.42 Rearend in it. That car I guess has around 120K miles, but the rearend is good and has drum brakes on the back like mine does stock. Now i'm moving to FLorida in august and I want my Formula to be very very reliable, so I'm getting everything done to it so its ready to be a Daily Driver. My buddy wants $150 fo rthe rearend. My question is should I get a posi unit, and if so whats the best options for me. I heard SLP has one for like $100.Can you guess help me out please and offer some suggestions. Also, other than 2 inches, whats the biggest diffrence between the rearend my friend has and a like 97 TA rearend, which is also a 3.42 or maybe a 3.23. WOuld I notice a diffrence from that one and a rear from a 86 or so?

 

The SLP posi works with 28-spline axles, an '86 has 26 spline. Unless you get later axles to go with it, the SLP unit won't work.

The least expensive route is to find a rear that has posi and the ratio you want. Next alternative is to put a PowerTrax into your friend's rear end. Other than some other used posi unit, you're looking at a new posi carrier, made for 26-spline axles, which will require professional set-up.

Really think you're going to need a posi in Florida?

 

Yeah I been thinking about just forgetting the posi and just putting the rear in. I havent talked to this guy for a week or so. But I will sooner than later. I called a yard and they said they had 5 new 4th gen cars just in recently, so when I get a day off pretty soon I'm going to go down and check them out. Does anybody have the specs on all 4th gen rearend specs from 93-02. And which ones have posi. I'll just bring that along with me to the yard. Thanks guys :hail: