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I am getting close to having the frame powder coated on the above car project. It currently has a 10-bolt out of a late sixties Oldsmobile, so now would be the time to do one of three things.


a.) Put a Pontiac 10-bolt with the right date codes, etc under this (late April build code, car has standard GTO engine, auto, air) or

b.) Forget putting an axle with the proper markings cast into it under this, and go with a early 70's 8.5" 10-bolt out of a Buick under it. My understanding is this is far stronger without going for a 12 bolt or (heaven forbid) a Ford 9-inch. Or,

c.) Split the difference and put a Pontiac axle from another year.


As long as the housing is intact, I'll probably wind up replacing all the wear parts anyway.

If you have one of the above options, let me know what you have available. I'm really not wanting to spend a ton on this.

Doug
 

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Locate an 8.5". Unless you are going for a 100% restoration and plan on locating a rear-end that would be specific to your car, I would want strength over originality.
 

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I have a YH Safe T Track with 3:55 to 1 out of an early 66 with low mileage that has never been apart. I know all the history and rear has never been apart but it is an original part and not cheap let me know if you have interest.

Thanks
 

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Good luck finding a cheap 8.5. Those, with the correct mounts, only came in a very few cars. I've read that some '71-'72 Buick & Olds A-bodies are the cars that had them. Most who have 'em know that. I'd plan on spending at least $2000 for a complete, and properly set up 8.5.

I think pinion head, who has posted here, has posted that he has some, and he can set one up correctly for you. Don't have a clue what his price would be, or what shipping would be.

Cheap, but decent 9" Ford set-up will probably be $2500. And, for $3000-$3500 you can get a nice 12-bolt with a new aftermarket housing.

Here's a cheap basic 9", with upgrades available. Some like this vendor. Some badmouth 'em. I have no opinion. They're just one source.

https://www.quickperformance.com/9-Ford-Complete-Rearend-GM-A-Body-64-67_p_20385.html

https://ls1tech.com/forums/gears-axles/1416301-survey-how-your-quick-performance-9-holding-up.html

There are probably some guys who can supply you with a rebuilt and set up 12-bolt for $2000-$3000.

https://www.ebay.com/itm/CHEVELLE-CUSTOM-BUILT-CHEVY-12-BOLT-REAR-END-EL-CAMINO-A-BODY-GS-OLDS-AXLE-DIFF/262191884074?hash=item3d0bdaa72a:g:S4IAAOxye3BRr9~-

Or, you can use what you have & stay on the lookout for a bargain, from some guy who needs some quick cash. If there is a drag strip near you where there are a lot of low budget bracket racers, they will know where some 12-bolts are & at least one local guy who can set 'em up for a reasonable price.
 

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Good luck finding a cheap 8.5. Those, with the correct mounts, only came in a very few cars. I've read that some '71-'72 Buick & Olds A-bodies are the cars that had them. Most who have 'em know that. I'd plan on spending at least $2000 for a complete, and properly set up 8.5.

I think pinion head, who has posted here, has posted that he has some, and he can set one up correctly for you. Don't have a clue what his price would be, or what shipping would be.

Cheap, but decent 9" Ford set-up will probably be $2500. And, for $3000-$3500 you can get a nice 12-bolt with a new aftermarket housing.

Here'a cheap basic 9", with upgrades available. Some like this vendor. Some badmouth 'em. I have no opinion. They're just one source.

https://www.quickperformance.com/9-Ford-Complete-Rearend-GM-A-Body-64-67_p_20385.html

https://ls1tech.com/forums/gears-axles/1416301-survey-how-your-quick-performance-9-holding-up.html

There are probably some guys who can supply you with a rebuilt and set up 12-bolt for $2000-$3000.

https://www.ebay.com/itm/CHEVELLE-CUSTOM-BUILT-CHEVY-12-BOLT-REAR-END-EL-CAMINO-A-BODY-GS-OLDS-AXLE-DIFF/262191884074?hash=item3d0bdaa72a:g:S4IAAOxye3BRr9~-

Or, you can use what you have & stay on the lookout for a bargain, from some guy who needs some quick cash. If there is a drag strip near you where there are a lot of low budget bracket racers, they will know where some 12-bolts are & at least one local guy who can set 'em up for a reasonable price.
Craigslist can sometimes produce the 8.5" 10-bolt, which can be reasonable in price or outright stupid. Believe it or not, I just snagged one at my local Pull-A Part from a totaled out and boned out 1972 Buick Skylark 2-Dr HT - $140.

Building the 8.5" 10-bolt can also add up, but still easier to get than a 12-bolt and much cheaper. Correctly built, it will handle most anything you put in front of it. I have read that the pinion is slightly longer so you will have to shorten the driveshaft about 1".

The "Corporate" 8.5" 10-bolt was introduced in 1971 and found under 71-72 Cutlass/442 & 71-72 Skylark/GS. A quick way to ID is all 8.5 rears will use 4 bolts and the 2 strap yoke system (instead of the U-bolt straps Pontiac used), a 1 1/4" nut holding the pinion yoke on the pinion gear, and you will see a cast lug or step on each side of the housing at the bottom near the rear cover. From what I read, Pontiac did not use the 8.5" in 1971-'72 A-bodies. They did use the Chevy 12-bolt on the 455's.
 

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I have a XK posi out of a 1969 Judge. I has the four spider gears and the big N for nodular. It is too low geared for my application. Currently under the car so I will have to replace with 3:23 or 3:08 posi if I can find one. Don't know a fair price? I'm in the OKC area so shipping would be a question also.
 

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Close, but that 3.90 is probably a bit too steep for what I'm building, and if I have to change gears, the value goes way down for me. Shipping would be no problem for me. I live in Austin, TX which is only 5-6 hours away. PM me your bottom price and I'll let you know.
 

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Yep. Deep gear is why I'm selling. I'm looking to get into a 3.03 - 3.23 posi unit. I will be giving up the heavy duty nodular case and special forged axels that came in the XK. I am hoping to find a street racer who needs a launch gear. I'm asking $2000 for the unit which is in extremely great condition. The insides look new. Let me know if you run across an extra posi unit with the higher gears out there. Thanks
 

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I am getting close to having the frame powder coated on the above car project. It currently has a 10-bolt out of a late sixties Oldsmobile, so now would be the time to do one of three things.


a.) Put a Pontiac 10-bolt with the right date codes, etc under this (late April build code, car has standard GTO engine, auto, air) or

b.) Forget putting an axle with the proper markings cast into it under this, and go with a early 70's 8.5" 10-bolt out of a Buick under it. My understanding is this is far stronger without going for a 12 bolt or (heaven forbid) a Ford 9-inch. Or,

c.) Split the difference and put a Pontiac axle from another year.


As long as the housing is intact, I'll probably wind up replacing all the wear parts anyway.

If you have one of the above options, let me know what you have available. I'm really not wanting to spend a ton on this.

Doug
May hav some of those but hav question also
What year application?
 
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