Rear Differential for a 65

[Murray S.]

I am looking for the following rear end:
65 Corvette
Code: AN
Ratio: 3:55

My car was assembled in November 1964, so I am looking for a casting date of:
9-NN-4 (September 64 casting) or
10-NN-4 (October 64 casting)
In my examples (above), 'NN' represents the day of the month, so any 'day' would be acceptable.


I do not need a complete unit since I have most of the other components; I am interested in just an empty rear end case.

My contact information is as follows:
e_mail: murray_sobol@dbcsmartsoftware.com
Phone (work): (519) 893-1436 Ext 280 (9:00 AM to 5:00 PM EST)
(home): (519) 846-0196

[Harry S.]

Re: Rear Differential for a 65

Murry, I would not worry about the casting date. I would be more concerned about the build date stamped into the housing. This date along with the other stamped characters reveals the gear ratio.

I have an April 63 car, the cast date on the rear is December of 62, but the stamped build date is 10 days prior to the car build date in April.

Give Pat a call to see what he has:

http://cgi.ebay.com/ebaymotors/CORVETTE-DIFFERENTIAL-HOUSING-DATE-CODED-1963-1979_W0QQitemZ150275927164QQcmdZViewItem?hash=item150275927164&_trkparms=39%3A1%7C65%3A10&_trksid=p4506.c0.m245.l1318

I don't know your price point but it's a place to start.

Harry

[Murray S.]

Re: Rear Differential for a 65

Harry:
Thanks for the contact info.
I was under the impression that a 3:55 gear ratio was a 'AN' code, but guys at Ikerds tell me that it should be a 'CC' code. I got my information from the NCRS judging manual.
Also, what is a typical 'lead time' between casting date and build date?
I thought that 2-3 months would be typical; since my car is a third week of November 64 build and most of the original parts on it are dated September 64, I chose September 64 for a casting date.

Murray

[Harry S.]

Re: Rear Differential for a 65

Murry, I'll look for more info later as I'm painting at the house today. A September casting date can have a January build date stamped into it. That would be after you car was built. The stamped build date or assembly date should be a few weeks before the car build/assembly date. The casting date on the rear is essentially meaningless as the guy building the rears pulled what was available next or closest to his work station.

Do you have Noland's book. There are examples in there. (VIN and rear dates)

Harry

[Wayne M.]

Re: Rear Differential for a 65

I am looking for the following rear end:
65 Corvette; Code: AN, Ratio: 3:55

My car was assembled in November 1964, so I am looking for a casting date of:
9-NN-4 (September 64 casting) or
10-NN-4 (October 64 casting)

Murray -- you could not have picked a more difficult diff case to obtain. First, code AN is correct (CC is 3.55 for '63-4). Second, 3.55 posi's are rare. Third, there was the Sept/Oct/Nov strike at St.Louis and probably affected Corvette components at upstream casting facilities. You probably will not find an Oct '64 carrier casting (J-NN-4, in your example).
Fifth, there was a change in design / part # sometime in early model year '65, with early carrier #3818753-N and the latter being 3876476-N. Visible difference being the foremost hole where the diff bracket attaches is threaded for '63-early '65, and thru-bolt for later. Also, rear cover may be a "3830303" (not a "3871375", yet may have the tapered (NPT) fill plug associated with the "375 cover" -- not fine thread like '63-4. Rear cover plug design could vary, depending on "303" casting mould #.

An example would be my car #014xx, completed first day after St.Louis strike ended, with early items mentioned above.

Generally, the carrier cast date is FAR ahead of the assembly date (compared to other cast items), as posters have mentioned. G-4-4 (July) in the case of mine, which was assembled AP_9-17-64. Another late Jan '64 car rear end I have was cast J-18-3 (Oct '63) and assembled CF_1-3-64 (Jan '64). A late '65 BB diff I have was cast D-5-5 (April) and assembled FA_7-15-65 (July).