I have a 89 Trans AM T5 with 3.08 rear end and I'm dropping a 383 stoker into it. I am assembling the motor right now. With this project I'm running out of money and I am concerend about my rear end. I just got it rebuilt with new bearings and a new 3.08 gear about 500 miles ago before I started working on the motor and doing a paint job. My question is, what spline axels does my car have? I heard that up to 88 they used 26 spline axels and then in 89 and up they used 28 spline axels. If I have the 28 spline axels then I was going to get a Rear end gurdle from Summit and put a 3.73 gear in it. I was hopeing that would be enough to take the 383 that going to make 450-500 lb.-torque. What do you guys think?

 

what differance does it make how many spline axles you have to the girddle? 89 could be either 26 or 28, you'll have to pull one and count.