ive come across a set of brand new 4:11 gears from a 60s nova 10 bolt that i can get really cheap. i know the axles are different between the two cars but are the insides the same?

 

Probably not... The old Nova is probably not a 7.5" 10 bolt. Besides that, the gears are the cheap part. Where it gets expensive is the install, and the carrier if it has to be changed.

Unless someone's changed the rear end, your 87 Iroc should have a 3.27 limited slip 9 bolt. If so you need gears for a Borg Warner 9 bolt.

 

i figured they are different but i dont know much about axles so i just wanted to know for sure

 

The old Nova rear end is a 8.2 10 bolt. Your car has the 7.5 10 bolt. The only parts that will interchange are a few bearings. No other parts will work.