I Just bought a 1987 Iroc-Z.. I need to know ALL the information i can about the rearend. Where can i look to look up the stamped #'s and all that. I need to know size (7.5 or 8.5 or whatever) and 9 or 10 bolt.. I would just like to know i can tell

 

get under the car and look, then you'll know what you have. you can look the stamped code up in your manual or rpo decodes.

 

For starters you can look underneath and count how many bolts are holding the cover on the rearend.

 

If its a 9-bolt and hasn't been messed with...

Limited Slip - will have a metal tag at the (4:30 clock) position.
Gear Ratio - Will be stamped on a tag at (9:00 clock) position.

Use a wire brush to clean it up. I'm not sure on the 10 bolts.

 

If it's a 10 bolt look on the front of the drivers side axle tube. You should find the axle codes there, somewhere under the rust.