In contact with a guy selling a posi that he says will fit 68-72 A body but don't know what it came from. The numbers on the pumpkin are as follows:
1375689
Says he can't find any numbers on the tubes or anywhere else. Any help?

 

Bueller? Bueller? Lol
Anyone have any idea?

 

You may want to describe the rear cover as to the shape and number of bolts and if it is smooth or has a rib and if axles bolt in or not.

 

If it is from an A body, it will have a 2 letter code, stamped (usually upside down) on the rear of the PS axle tube, about a foot in from the brake backing plate. Often it is obscured by smutz and a wire brushing in that area will reveal the code.

 

Here's a pic that I have of it. I know I've been asking a lot of questions about motors and rears lately and I appreciate the help. I had surgery the end of Feb to reattach my bicep to the bone so I'm not able to crawl around etc like I want to at this time but before summer is over I will. I'm trying to score parts etc while I can and formulate a plan of attack but just found a running, complete 455 for a decent price so that's where I'm gonna start.

 

I am no expert but appears to be a Pontiac style 10 bolt cover rear. Someone can turn axle 1 time and count turns at driveshaft mount to get ratio if no letters to ID it are found.

 

This is the stamping from the original 8.5" 10 bolt from my 1971 convertible. Note that there is a 2 letter code, but also some other information as well (date code?). The earlier O-Type 12 bolts had a simple 2 character alphanumeric code.

197110boltR2256opendiffcomp.jpg

 

Pontiac. This is a shot of a 69 RA3 Judge. What are you planning to bolt it into?

 

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Agree. Both the OP and your photo look alike as does my photo of 67 GTO rear end (10-bolt BOP style) in my '47. Mine is an 8.2 rebuilt with Auburn limited slip and new 3.55 ring and pinion and all bearings. Rebuilder said it would do fine behind my slightly warmed up 455 as long as I didn't run slicks and race on weekends.

 

Look at this link

http://www.oldsmobility.com/old/10bolt-tech.htm

 

code stamped if unit came installed in a car from factory. NO CODE STAMP on a housing purchased over the parts counter. I have had several without a tube stamp.

 

Remove the cover and take pic and post. The gear tooth count is stamped on the outer edgeof the ring gear. like it may be printed 10 GM 39 or something similar.in this example 10 and 39 would = 3.90 ratio. divide ring gear tooth count by the pinion gear tooth count to get ratio. Posi vs open is visual.

Yours looks like a Type P that may have come installed in a 66 or 67 442? ( or any GTO of that era)

 

This guy is 1.5 hrs from me so I'm not taking a ride just to look because this guy don't want to look anymore. I guess he isn't that interested in selling. He don't know what he has and is unwilling to try to help. He can sit on it....there are others out there. Thanks for trying to help guys.

 

I know this is OLD but it looks like it needed finishing.

It is a BUICK casting they were used in the Oldsmobiles along with the Pontiac.
Pontiac was the high horse rear in early 1967 OLDS cars the Buick 10 bolt 8.2 was a lower regular car cutlass rear a driver so to speak. BOTH rears use the same ring and pinion so really it is a MOOT point unless your getting that number matching CRAZY.