i have an 82 Z28 with a 350 motor and TH350 tranny. due to some recent vandalization, i have to replace my rear end and many suspension components. now, ive heard of many people putting a fourth gen rear into a third gen, but im unsure about how well this will work. i know the fourth gen is a bit longer on the axel ends, but i dont know how everything elso will work.

will the rear end bolt right up or will it require metal work?
what suspension components will be need to be replaced?
what kind of gear ratios can i expect from a junk yard fourth gen rear end (probably a v6 car)?
or would is simpy be easier to get a replacement third gen rear?

the reason i want a fourth gen is most of them have posi and disc brakes, two option my car is short of and are pretty rare for third gens.

any info would be most appreciated, thanks in advance for your help.
the King

 

The mounting points are identical between the 3rd Gen and 4th Gen rear axle assemblies. No suspension components need to be changed. Its a direct bolt-in.

The 4th Gen rear is 2" to 3" (according to the Strange website) wider than the 3rd Gen, so you need wheels with a lot more positive offset.

Brakes will most likely be different, if you don't have a disc brake rear in your 3rd Gen.

The 4th Gen V8's came with 2.73, 3.23 and 3.42:1 rear axle ratios. All 94 and newer 6-speeds had the 3.42s. All A4's and the 93 6-speeds had the 2.73 and 3.23 ratios. Only the V8's had posi as standeard equipment. On the V6's it was an extra cost option.

If the chassis still has the build code tag:

GU2 = 2.73
GU4 & GU5 = 3.23
GU6 = 3.42

 

Great, that helps me out a bunch. thanks for all the great info!

 

3rd gen brakes will work fine on a 4th gen rear, you just need to swap over the 3rd gen backing plates. If you want to use the 4th gen rear disc brakes you need to convert to a proportioning valve out of a 90-92 f-body or buy an adjustable one. The 4th gen rears are 2" wider on each side, but you can use 4th gen wheels just fine. They should fit in the front without spacers? Anyways, 4th gen rears are stronger than 82-88 3rd gen rears because they use 28 spline axles in place of 26 spline axles. That, and a better posi/limited slip design. They aren't that much stronger though, so don't get too confident in it! Oh, and try to find a rear out of a V8, like Fred mentioned the standard posi would be nice to have!