First off, I have a 73 buick apollo that currently has a 350 2bbl with a 2.41-2.56ish open rear. But I am putting a 455 with maybe 400hp 400 torque in it. I would like to run a small stall converter in it as well. There is a posi disc brake rear out of a fourth gen lt-1 camaro at my junkyard, I measured and mearsured and it seems to be about 4.5 total inches wider disc to disc than my original drum to drum, which means it will come out about 2.25 on each side. Could wheels with different backspacing hide this a bit. I looked at my rear with the current wheels (which will change anyway) and it seems that I can afford to be a little wider but not sure how it would look. The rear of the car sits high because of the air shocks and it seems like it will bring the rim out and be alomst even with the lip of wheel well. I know that on some cars this looks silly but on others it looks great (my corvette is one of them) I understand that the 7.5 rears aren't the strongest and another option I am looking into is swapping the 8.5 carrier and possibly axles but its much easier and cheaper for me if this camaro rear would work. I have searched here as well as the net and gotten a lot of info. This is my first time asking so I am just curious what my fellow x body(ers) thought. Thank you very much!
The high-back-end look also kills any chance at traction and isn't too safe at high speed, so you might want to keep looking for a correct width 8.5 (or maybe an 8.8 ford) rear to keep the car level or with just a slight rake. If you want big tires, that means mini-tubs and possibly relocating the leaf springs for clearance. It just depends on how wide you want to go with the tires. Nice job with the illustration!
8.5 10 bolt reard are a dime a dozen (ok, maybe a little more then .10) but are very pleantiful. i would look for one of those they are very strong, under apreaciated and under rated. not to mention it will bolt right in.
Yeah I guess I'll just find a posi carrier and do it that way. My wife did her 78 nova that way with eaton internals and 3.73's and it was nice! It's just so hard to walk away from a posi 3.23 disc brake rear end sitting in the junkyard for $100 ya know....lol My 75 olds omega as well as my two 73 buick apollos are all 8.5's. The apollos are open rear and like 2.41 or 2.56ish gears and not sure about the olds but its a 250 l6 so I would assume the gears are a little steeper but def not a posi. By the way no updates yet because I am still "parts stacking" and learning about buick engines. As well as tearing down the 455 to get it ready for "test fitting" and the machine shop. Thank you to all!
Buy the junkyard rear and sell it to someone else for a profit, then use the money to buy a good 8.5 inch rear. My 76 Skylark has the stock 7.5 inch open rearend, but it will eventually be replaced with a 9 inch Ford.
Yeah thats true...but I know what will happen when I get it home....I'll say to myself "I will be able to use it for something eventually" LOL
X bodies had 2,73, 3.08 and 3.43 rears as options in the 8.5's. 7.5 were in later (75 and newer) with the 6 cyl. engine. Ben.
if i'm not mistaken, the apollo's had a different width from the later skylarks. i used a 70 camaro rear in my lark, but had to move the spring perches in.
If you want rear discs, why not consider the 76-79 Seville rear disc setup? Those Sevilles had many similarities to the 75-79 X bodied cars-type of subframe, front suspension, rear axle housing, etc.
Let me know how your 350 to 455 swap goes. I have a mint 15,000 original mile 74 Apollo with a 350 4bbl. runs out relly well, but I also have a very strong 455 in my garage---just haven't the courage to alter a completly original car....yet. Ben.
'68 up Nova platform sub-frame car rear ends work. The '70-81 F-body(Camaro/Firebird) does not, it is wider, spring perches and overall width. Look for a '70-74 Nova (look for a four door), most of them had 8.5 10 bolts, then seek out a Suburban with a tow package for the 3.42 or 3.73 posi. Takes less horse power to drive than the 9 inch. The brakes fit, gotta' shorten the drive shaft 3/4 - 1 inch. 8.5's are still in production in 1/2 ton pick ups for gears and posi's.
I ran a camaro 8.5 in my skylark with strange 31 spline axles and a hytuff spool. The total cost for parts was 1400 cdn from bears in Windsor. Bearsperformance.com. They have everything you need to make it hook and build it bullet proof. It may sound like large coin but spend money wisely and once and you will get more enjoyment and less frustration in the long run. I consistantly run 509 horse and 125 to 150 nos and still havent spit a tooth or axle. My 0.02 cents
does anyone know what spline count these rear ends are? I have a bone stock 1974 with a gm 8.5 and I want to order a posi unit before i open the rear end up. Thanks! o No:
I found 28 splines axles in both a 2nd gen Camaro and '77 Cadillac Seville 8.5 rear ends I've pulled.
Also, some of them (and their baby Blazer and cousins) have the rear DISC setup!!! Usually on the higher end models, start with 3.08 gears, some have 3.42 gears!!! If it has the 16 inch wheels, odds are it has the 3.42 gears. Look inside the door for wheel size from factory if gone.
