hello everyone i am new to the whole car seen so i just need to know a few things . I have a 85z28 in with i am fixing up soup to nuts so i would like to know what type of gears came stock in that year. and what type to replace them with.

Your car will have a 7.5" 10 bolt differential. I can't tell you what gears it will have without more information. It'll be 3.23 or 3.08 unless it's an IROC, then it'll have a couple of other options.

Engine (probably be a 305), transmission (A4 or M5), induction system (carb, TPI).

You can also look up the RPO code if they're still in the center console to see what gears the car originally came with.

If it's an IROC,that came with TPI, and was built late in the production run, it could have the Australian 9-bolt. That should be 3.27:1

Didn't think that happened until 87 for the Camaro.

JamesC