Is this an early 57 Posi??

[Dick G.]

Can someone ID this rear end for me? [IMG]http://i50.tinypic.com/ogco06.jpg[/I
Thanks
DG

[Harry S.]

Re: Is this an early 57 Posi??

Might be!

http://i50.tinypic.com/ogco06.jpg

[Mike M.]

Re: Is this an early 57 Posi??

Might be!

http://i50.tinypic.com/ogco06.jpg

the differential case of a 57 posi has a casting # of 3743833.mike

[Dick G.]

Re: Is this an early 57 Posi??

Harry
What did I do wrong with my upload at tinypic? Thanks For helping me out. I gave up on the process. High blood presure and all. So, what car was this posi used in oriignally? Maybe a 67 chevy? I will be selling her. Just trying to educate myself.
Regards
DG

[John H.]

Re: Is this an early 57 Posi??

Dick -

The 812 is a Posi center section casting, but it didn't appear in Corvettes until 1961; that one's a "thin P" casting machined at Detroit Gear & Axle, but the "6" as the casting date year says it wasn't "born" in a Corvette. What's stamped on the passenger side front face?

[Dick G.]

Re: Is this an early 57 Posi??

I have looked for the stamping and cannot see anything. Twice I have wire wheeled this passenger side area and see nothing. The previous owner of 30 years claims he got it over the GM counter after he blew a hole in the old 60's rear center section years ago. This car was parked in 76 till I bought her.
Thanks DG

[Tom P.]

Re: Is this an early 57 Posi??

I'll reply to this for you exactly the same as I did over on Corvette Forum, nothing's changed:

"It IS a posi-------------THAT'S WHAT THE BIG P INDICATES.

It is a SERVICE REPLACEMENT posi, assembled at the Detroit Gear and Axle plant.
The casting date is K16=Nov 1, 1966-------------NOT, repeat, NOT 1956. Therefore it is the later (60-64) style posi unit---------the better unit!
The OTHER side SHOULD have a two letter code followed by 3-4 numbers.
The very LAST year for this style to be FACTORY installed in a Vette was 1962 and for pass cars, 1964.
Thus, since that rear has a Nov 66 casting date, it would have been sold over the parts counter. If I remember correctly, the only ratios sold as a complete posi unit were 3.70, 4.11, 4.56. If a person wanted a posi ratio other than those 3, then they had to buy the case, posi unit and ring and pinion set and assemble it.

That rear has NO valve as a restoration rearend for any car because of the 66 date. It IS valuable as a posi rear if it is in good condition. These rears were still assembled for 2-3yrs AFTER regular production of the 64 models ended (the latest dates that I've seen on cases and ring and pinion gears is 66), and were available until parts inventories ran out. I bought a 3.55 ring and pinion set about 1967, but back then it never occured to me to look at the date code on the gears."