What are the differences between the two besided the option of an 8.5 vs 8.2. I read somewheere the spring perches were the wrong distance. Any help, I'm looking for a $30.00 8.5 but I can't seem to find old Nova's rears out here in bone yards for cheap.

Spring perches are 1 1/2 inch wider.

I see the old 8.5" Nova rear ends all the time here in Fairfield. If you wait till half price day you can pick one up for $60 or so. If you're real smart you can swap out the gears for some from a 80's GM 4x4 front diff and get the gears you want in the same package.