[Eric327]

Ok iam obviously going more power and i need to upgrade from my 7.5 in my 1986 monte carlo ss and iam going too need an 8.5 rearend. I hear they will bolt right in out of a Grand National (lmao nearly imposoble to find and if i do very expensive). But is that the only car that the 8.5 is found in that it will bolt right in or is there another car or cars that it will work?

[69 Byrd]

Looks like there are a few - check out this link.

10 bolt

[curtis73]

The hi-po G bodies have the 8.5 and its a bolt-in. That website is a fine reference, but don't listen to that guy.... He said the 8.5 is tought to find parts for... is he NUTS? The 8.5 is the most widely used GM rear EVER. Parts practically fall off the shelves into your lap for that rear.

Look to the Grand National and Olds 442 G-bodies. The Monte SS had the 7.625" (same as the 7.5 with a different ring gear) but just skip it. Find an 8.5 from one of those two above and you'll be fine.

No other vehicle will offer you an acceptable width. You could narrow an axle from another donor, but it would cost more than just buying an axle from one of the above cars. You can also do your own sleuthing. Many salvage yards have flat-rate prices on axles. Find a junkyard like that and just grab an axle from a 442 or GN. Chances are they've been picked over first, but there are always other junkyards. Most flat-rate yards charge about $150 for a complete axle.

[Eric327]

wow man thx for the opinions and the replys. But i didnt know t types had them in it. Man i can get 1 right now for about $100 thanks alot man. TY TY big help.

[GEARHEADWV]

<84 monte ss I found my 8.5 from the web for ~$300 then i put a new carrier (eaton) and 4.10s in it. If i remember right some of the older t-types still had the 7.5 10 bolt. Make sure you get a year list that had the 8.5. You can tell the difference by looking at the "ears" on the bottom of the rear end. 7.5 has narrow looking **** on each side. 8.5 has a squared corner look to it.

Im wanting to think they didnt put the 8.5s in till the year of the GN or the year before. I looked at a 79 or 80 t-type that had a 7.5 in it.
hope this was some help.
Aaron

[Guy Hiltz]

Hope you find a 8.5 from a Hi-Po G Body,here in Nova Scotia they are impossible to find.I had my buddy looking for one for two years,he specilizes in getting all different kinds of rearend and operates a fairly large salvage yard.I ended up going with a custom made 9 inch Ford and I have no regrets,it is standing up to my solid roller cammed LS-6 big block.One advantage was that the Ford rear had considerably bigger brakes.But the 8.5 is reputed to be a very tough rearend.

[curtis73]

Maybe its just where I've looked, but I have no trouble finding them. I went to one 'yard in Evansville Indiana (Liberty Pull a Part) and found three out of 12 G-bodies on the lot. Here in CA there are literally thousands of boneyards with 8.5" Gbodies in a row. Nobody modifies Gbodies here in CA because they're still under smog control, so why bother upgrading axles? For the same reason, they are also some of the first to get crushed. PLEASE... come to CA and save some 8.5" Gbody axles. In backwoods Franklin, PA I found two 8.5" Gbody axles; one in a 442, the other in a GN. It was one of those big mudpit boneyards with flat pricing, so it didn't matter if I yanked a posi 14-bolt or an AMC 20 rear, it was $125. Period.

Find some big boneyards, take your toolbox and an oxy-acetylene torch and have fun. This makes me wonder... I could probably score 4 of these axles in one day up in the valley. Maybe I should do that and take them to Spring Carlisle and make a fortune.