Im looking at a 12 bolt and the seller gave me this number R80212K.

What is this out of? I asked him to give me the eight or nine digit/letters off of the housing but with what he gave me is that enough info to figure what its out of? Any help appreciated!

I guess no one has any ideas??

R8 show's as 1968 Old's type C w/2.56 gears open diff. and 1969 Old's type O rear W/2.56 gears open diff.
You'll need the casting date and casting number.

R8 show's as 1968 Old's type C w/2.56 gears open diff. and 1969 Old's type O rear W/2.56 gears open diff.
You'll need the casting date and casting number.

So this is not a Chevy type 12 bolt. The BOP (Buick, Olds, Pontiac) 12 bolts are not as strong as the Chevy 12 bolt and aren't worth near as much in my opinion.

So this is not a Chevy type 12 bolt.
I wouldn't jump to that conclusion just yet.
The casting # and date will tell more.
Old's used the Chevy c-clip 12 bolt 68-70 so it should be a Chevy type.
The 8.5" O type was used those same years.

I wouldn't jump to that conclusion just yet.
The casting # and date will tell more.
Old's used the Chevy c-clip 12 bolt 68-70 so it should be a Chevy type.
The 8.5" O type was used those same years.

True. But based on the R8 code, which is all we have so far, things are not looking good.

Look again what I posted.

68 is a c-clip rear
69 is a o-type rear

Mike, you may be right. Not trying to argue. Agree that we need more information.

Gene, what does the rear end cover look like? Can you post a picture of it?

No problem Byron ,didn't know if you saw the c-clip for the 68.
Thought it was a mis-print with the same code for o & c type rear's but multi sources show the same.

Mike, can you send me a PM with more information about Olds using the C type axle in 1968? I guess I thought only a very limited number were ever installed (I have never personally seen one in an Olds) but would like to learn more. Thanks

Well ,can't send the part's catalog or the Hollander but here's some info that may help:
http://www.oldsmobility.com/reardiffs.htm
http://www.oldsmobility.com/10bolt-tech.htm
http://www.442.com/oldsfaq/ofdif.htm

The 12 bolt c-clip was only used 1 year in the Old's A body

Thanks Mike.

You have a pm also.