My tbird was built on Dec 27 1956. It is a 312 it had a automatic trans. I think the the numbers on the air horn should read list 1273-1 ad. The date code should be 6 ? 4 another words 1956 dec? 4th week. Right? all I really need is the letter for the month of Dec.  OH and of course the carbureator. HA Thanks guys

I would think the date code  needs to be some time before build date, not same time. IMHO

There was no just in time shipments back then so it could be weeks before the car was assembled.

Butchering up everything I can get my hands on in Dayton Ohio

The TBird Restoration and Specifications Manual show the following for a 57 312 with Auto trans:



ECZ-AD List 1273-1

ECZ-V List 1272 (Replacement).



The month in a lot of Ford date codes start with the letter A for January. I don't know if any letters were skipped




54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

layourman

Here is one i saw on ebay

http://www.ebay.com/itm/1957-Ford-Thunderbird-Fairlane-312-High-Performance-Holley-Carburetor-1273-ECZ-V-/140658141176?pt=Vintage_Car_Truck_Parts_Accessories&vxp=mtr&hash=item20bfe0e7f8

Gary Ryan San Antonio.TX.

I believe that the Ford casting dates codes are 1-January, 2-February.........9-September, 0-October, A-November, B-December.

Randy

The Holley date codes are different than what Ford used.  Early model Holley carbs used either a 3 or 4 number date code.  For the 3 digit code, the first digit is the year, second digit is the month with A and B being used for November and December respectively, and the third digit is the week.  The four digit codes are more complicated and became the standard numbering on the Holley carbs starting in 1972.  But if you have a four number code, then the first three numbers are the consecutive day of the year starting with 001 for Jan 1 and ending with 365 for December 31^st.  The fourth digit would be the year.

Lorena, Texas (South of Waco)