I have searched all over. Is it a 9 bolt?

Should be a 9 bolt with 3.27 gears.

Count the bolts on the diff cover (IIRC, the cover should have a rubber plug).

JamesC

I will, but I don't pick the car up until Sunday. I was just trying to research it a little bit.
So there'll be a rubber plug in the cover?
Thanks guys.

Well, my car has a LS 10 bolt... Anybody know how I can identify where it came from?

Is the 10 bolt better or worse than a 9 bolt?

Depends how you look at it. Technically the 9 bolt is a little bit stronger but not by much. A 10 bolt can be better because it has greater aftermarket support.

Neither is great compared to using a third gen Dana 44, if you can find one, or using an aftermarket 12 bolt, 9" or Dana 60.

What's an LS 10 bolt?

The diffs under third and fourth gen cars are virtually identical with some slight variations. In 1990, they were upgraded to 28 spline axles from 26. The ring gear size increased slightly from 7.5" to 7.625 around 1986. Depending on the engine, transmission etc, they could come with or without a posi and in just about any gear ratio. Brake options changed over the years but that adds nothing to the strength of the diff itself. A fourth gen diff is about 2" wider on each side. A diff in a V6 car is really identical to a V8 car's diff with no difference in strength.

Thanks for the information. Did GTA's come with 10 bolts, or was this something that was swapped in?

LS = Limited Slip

Yeah it was probably swapped in. An 87 GTA with a 5.7L TPI should have a 9-bolt 3.27 ratio as Stephen first said.