Topic: 1966 SJ Mustang Coupe Build Date Help

[jameslgleason]

I’ve been working on a 66 GT Coupe and am wondering about missing information, namely the approximate build date of the car. The doors seem original and have the GT light cutouts, but no warranty plate on the driver’s door.

It did come factory with the proper radiator support punched holes, the under seat exhaust supports, and the rear frame rail exhaust hanger supports, so I’m pretty sure it’s a factory GT.

It’s currently hanging on a friend’s rotisserie and I’m finishing up the rust repair (cowl & floor pans). I just took the engine apart and took it to the machine shop for a short block job. The machinist commented that it’s all original inside (bearings, pistons, etc.) and no one has done a prior rebuild.

Here are the details that I do have (although it looks like prior owners mixed and matched various parts over the years).

VIN: 6R07A218676
Year: 1966
Plant: San Jose, CA
Body: 2 Door Hardtop
Engine: 289 4v V8
Unit: 218676

Engine Block: 6E20 (1966, May 20)

Rear Axle ID Tag: 6AC (1966, January 3rd week)

Steering Box ID Tag: 6F08B (1966, June 8, shift B)

I have a friend with a 6F07T255572 with a build date of 14B (February 14, 1966).

Since mine is just 36,896 less, does anyone have any insight into how I can dig deeper into this mystery? Any help would be appreciated!

[JohnB]

6R08K125298   76A   R   26   29K   51   3   5   K   R

Datecode 29K = October 29, 1965

Look for more here; http://www.early-mustang.com/index.php/64-66-mustang-registry

[jwc66k]

John,
Welcome to the forum.

VIN: 6R07A218676
Year: 1966
Plant: San Jose, CA
Body: 2 Door Hardtop
Engine: 289 4v V8
Unit: 218676

Engine Block: 6E20 (1966, May 20)

Rear Axle ID Tag: 6AC (1966, January 3rd week)

Steering Box ID Tag: 6F08B (1966, June 8, shift B)

Using the Mustang Production guide, your VIN is in the range of the 17th to the 20th of June, 1966 for a scheduled build date. The steering box date falls in that range as well. Keep in mind that this a "scheduled" build date, and the actual may be a week or two ahead of behind that date.
For a new door data plate, see Marti Auto https://www.martiauto.com/index.cfm
I hope you understand that Ford Motor Co. destroyed all assembly line build information for 1966 and earlier Fords.
Jim

[jameslgleason]

Thank you! That's very helpful.

[GT500KR]

I have a friend with a 6F07T255572 with a build date of 14B (February 14, 1966).

Since mine is just 36,896 less, does anyone have any insight into how I can dig deeper into this mystery? Any help would be appreciated!

You are comparing vin numbers from two different plants, his car was built in Dearborn, yours in San Jose. So the difference you reference is not a mystery.

[jameslgleason]

Thank you!