I have an '88 TA w/ a pretty severe vibration that I"ve been fighting for a while now. I'm basically at the pt where the only thing left is either a bent axle, bad axle bearings, or teeth broken off the differential. So I figured I might as well just swap out a rear end and cover all of those bases at once (not to mention it's cheaper!)

And if I'm gonna swap out the rear end, I might as well upgrade from the 7.5" (?) rear w/ no posi and drum brakes to the 8" w/ posi and disc brakes. However, I'm only interested in doing this mod if it's not significantly more expensive and harder than just doing an equal replacement.

I've been searching on this and I know I'll need a new proportioning valve -- how much does that cost? And I can't seem to find a definite answer about how the e-brake cables hook up... it looks like I'll have to fabricate brackets? Should I stick w/ a 3rd gen rear end or go w/ a 4th gen?

 

I don't think you'll find an 8" that'll bolt into a thirdgen. The bigger 10 bolts came in the older cars and thus were leaf sprung rears.

But, to answer your question it's not hard to get the discs o work. Do a search on this forum and you'll find an article on how to mod the stock drum prop valve. Other than that it's just a matter of tweaking the stock lines.