C2 Differential Decode

[David P.]

Hello to All,

I was wondering if some of the experts wouild help me decode the differential for my '67 327 Coupe. I am trying to determine if it is original to the car.

It is stamped:
AN 42865

What I have found is that AN is 3.55:1 for all C2 years a but some places it says 3.55:1 Posi and some places say just 327 3.55:1, depending on the year.

Based on the first two numbers being the month and the next two numbers being the day, at first glance I thought:
April 28, 1965.

But then the last two characters are supposed to be two alpha digits indicating plant and posi or not.

But the last two characters on mine are not alpha, they are numbers, namely "65".

What do the experts say?

Thanks in advance.

Sincerely,

DAP

PS: My apoligies if this has been covered before. Being a new member, I am not sure where this information may be posted. Some pointers on where to find the info., if available, would also be appreciated.
DAP

[Wayne M.]

Re: C2 Differential Decode

.......help me decode the differential for my '67 327 Coupe. I am trying to determine if it is original to the car. It is stamped: AN 42865.

It is 3.55 ratio posi for 327. No non-posi 3.55 ratios for 1965. Would be prefix AZ if for a 396 (and 3.55 posi). You are correct on your date interpretation. The suffix with a "W" (Warren MI) came in later years.

IMO, 3.55 is a nice ratio to have.

[David P.]

Re: C2 Differential Decode

Thank you.