I have a 91 Gta with a posi rear that consist of 2.73's. It's a 10 bolt rear also. I plan on swapping the gears over to 3.73's but i get asked about a size. 10 in. or 10 1/2 in. Can anyone help me out as to what their referring to? and also from right off the top of your head would anyone just happen to know the size?

 

7.5/7.625" 10 bolt.

You'll also need to change the carrier (posi) to a 3 series or buy the proper deeper gears designed to fit onto your 2 series carrier.