found a disc brake rearend in a bone yard out of a 89-90 firebird formula. they want $250 for the whole thing. good deal or not? also what gears did those come out with and are they 10 bolt then. Also i was told if it is a disc brake then it would be a posi. Dont sound right but any light on this would make my decision easier. thanks.

Very likely a nine-bolt with PBR calipers and 11.7 inch rear discs. Jerk the diff cover to see if it's a limited slip. I'd personally go $250 under those circumstances. If it is a nine-bolt, check the following link for more info:

https://www.thirdgen.org/forums/faq-...now-about.html

JamesC

thanks jamesc