12 bolt posi housing ID help

I was told this was a 66 chevy 12 bolt 3.73 gear. I have confirmed the gear but just wanted to make sure of the housing. Here is a pic of the stamping.
Casting numbers a 3875745N and stamped numbers are C10215 with a B and a E. Thanks for you help

 

I dont know about the casting #s. But if you are woundering if it is a Chevy it will have the inverted "V" on the cover. I bought an Olds rearend that someone put a Chevy cover on and only two holes matched up all the others had to be elongated to get the bolts through. I think this is your consern? Here are some web site that might help

http://www.oldsmobility.com/reardiffs.htm

http://www.442.com/oldsfaq/ofdif.htm#DIF Differential Codes

Alot of info to read...hope it helps,Dave

 

Ed,
If you look at the back of the pumpkin, at the bottom there will be a date code. It will either be something like B12 6 or 126 6. The beginning code will be either a letter (month) or day of the year (126) the last number is the year.
Duane

 

Thanks Duane

I have found the E is for Eaton posi and the B is assembly location? B is Buick?
I will check the pumpkin area for the date code.
Thanks Again

 

that's wierd, from what that olds gm differentials site is saying, there is no 10 bolt rear with parrellel ribing (but that's what i have), im having trouble identifing my 10 bolt rear

 

From what I've found out, the 'B' is for the plant in Buffalo, NY.

 

Thanks Scott

That makes alot more sense than Buick. That must have been for the 10 bolt housings.

 

My 12 bolt has the 'B' also.

 

Ed -

Do you still have this 12 bolt? Is it for sale?

 

CI code is 3.73 posi 1966 12 bolt

0215= February, 15

B= Buffalo plant

I think your first 1 is supposed to be an I. Those early 12 bolts are rare and hard to find most of the time. They are not as wide as the 68-72 variation and are very sought after because of this and their rarity. A Chevelle guy will pay big bucks if he needs this for his restoration!!:TU: