BK, glad to hear you found a 8.5 rear. When I got mine they were more plentiful, but more expensive. Of course I took mine taken all apart and put brand new bearings in the entire thing double checked all clearances and the clutch packs. We also checked for proper contact between the ring and pinion. It helps when you know someone with the heavy duty press and dial indicator. The car it came out of only had about 50k on it so everything on it was pretty nice. One thing I can tell you to check for is the drum backing plates where the brake cylinder mounts. Make sure there isn't alot of slop when you mount in a brake cylinder. If there is a bit of slop back and forth from miles when mounted you can weld in the corners some (assuming your working with a good drum backing plate that isn't rusted galore). I hope this helps some of you in your searching. Keep in mind too that you will probably need to get a shop to cut down your driveshaft a bit to fit in the 8.5 properly (I needed to on my 80 SS ) & you should then get it rebalanced at the same time for your new gear ratio.