1957 Posi carrier 3743833 build code stamp

[John G.]

I have a 1957 3743833 X case Posi carrier, casting date B 7 7. The assembly stamp is 3 25 with the prefix AM for the gear ratio. I think this is a passenger car posi. I have a chevrolet by the numbers book for 65 on and a corvette numbers book for all years but I cannot find the meaning of this code. Can an expert in minutia enlighten me. Thanks. John

[Donald H.]

Re: 1957 Posi carrier 3743833 build code stamp

I'm sure the experts will comment, but here is a link to a thread that I started that has good info to decode the stamped numbers.

https://www.forums.ncrs.org/showthread.php?t=80328&uid=6730

[John H.]

Re: 1957 Posi carrier 3743833 build code stamp

I have a 1957 3743833 X case Posi carrier, casting date B 7 7. The assembly stamp is 3 25 with the prefix AM for the gear ratio. I think this is a passenger car posi. I have a chevrolet by the numbers book for 65 on and a corvette numbers book for all years but I cannot find the meaning of this code. Can an expert in minutia enlighten me. Thanks. John

John -

"AM" is a '57 passenger car 3.36:1 Posi axle code.

[Tom P.]

Re: 1957 Posi carrier 3743833 build code stamp

If you are fortunate enough to have an 833X posi case, and you want to put it in a 57 Vette, I WOULD NOT HESITATE to do so, to heck with the stamped code!!!!!!!!!!!!!
First of all, early 57 posi's are rather scarce. Second, the 833X was only cast for about 3mo during 57 production.