I have an 88 Iroc with the 9 bolt BW rear end, i also have a 91 Z28 with the GM10 bolt with drums, i was wondering if the rear disc setup is interchange able at all? or what i may need to put discs on the back of my Z28, like what cars can i get the backing plate and such off of, and what sort of valves and such do i need to make it work.....sorry the search didn't turn up the answers i needed

You can use the brakes but you can not use the backing plate. The 9-bolt has a different backing plate bolt pattern. I am sure you can easily find a set of 10-bolt backing plates for the pre-89 rear disc brakes for little or nothing because most people get rid of those brakes.

This exactly what I was going to ask today but someone beat me to it. That is good. My only question now is will the proportioning valve off of the nine bolt work for my ten bolt.