I have a 1989 iroc-z and not to sure what gear ratio is in it stock i always find conflicting numbers. but anyway my buddy has a Ws6 trans am 2002 and is going to give me his 3.73 gears while he goes for some 4.56 and i was wondering if they would just fit right in or if i'd have to but anything..
Any info would be great and save me some money .

 

Welcome to TGO. If the 89 rear is a 10-bolt, the gears will fit. If the 89 has 26-spline axles, which is probably does, you'll need to purchase a set of 28-spline. The following link will provide more FAQ will provide info that may be useful:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

 

You don't have to change the axles if you are just changing gears.

If your car has a 10 bolt and it has a 3 series differential then the 3.73 gears will fit. You will have to set the pinion depth, bearing preload and backlash. If your car has a 2 series differetnial then you will have to change that to a 3 series.

 

My bad. I'm used to recommending a limited slip swap as well.

JamesC