8.5 rear in my cuttlass
 

I was just wondering how strong my 8.5 rearend is and how much power can I put to it befor I twist an axle.I"m plaining on running a small slick and a full spool with 4.11.[/img]

8.5
 

I have run an 8.5 ten bolt in a 67 camaro with 600 hp and a 12 inch slick with a power trax locker and a 3000 stall about 350 eigth mile runs and never had a problem, saw a lot of proplems with the 8.2 rear end, the 8.5 is more durable then most give it credit for, the one thing your 8.5 wont take is a trans break if you are coming off the foot break where your drive train is loaded you will be fine.

camarotale got it right, you can also find it on the net and check
to see if your housing has small ears on the bottom, GM recommends
this one for rebuilding for torque, if no ears on housing, keep in
mind GM considers the no ears inferior. just check for yourself.
if you use good inners, w/beefy axels, it can take some abuse.
good luck buddy, and eleminate the "c" clips :wink:

Re: 8.5
 

I ran my 8.5 10-bolt with a just a mini spool and stock axles with 1.38 60' and had no issue's. I added the stronger stuff since then to be safe but the stock axles looked like new when I pulled them out. I think the biggest issue with it is weight. I was about 2750 then..

10 bolt 8.5
 

YEP, do alot of 10 bolt 8.5 rears....VERY good strong diff.

GM still uses this diff in the 1/2 ton trucks and suvs.

This rear has been in service since 1970!!! That is a darn long run for a diff...Can not be a bad design if it is still around. It is like the small block chevy of rearends...lol. It does it all.

You can upgrade it to 33 spline axles. I recommend 30 to be enough . You will be fine for about 400 ft # with the stockers as long as you have the proper elim kit give it a shot and see what she will take. If you have the money upgrade the spool and axles to 30 spline since this rear bolts right in. Then you should be good for down to 10's.

Trans brake is ok, but you will need to do something with the suspension to take that shock. Rears break because the suspension does not provide a sound delivery of the torque to the ground as a Ladder bar or custom 4 link provides. If the tires shake the rear ends tear themselves up esspecial if someone set the back lash to loose.

Good luck, Jim