What dates should be on the heads on my car?

[1971gsx]

I believe my car was built on April 7, 1971. What kind of date codes should I be looking for on my cylinder heads? How much earlier than the build date of the car can they be?
Thanks,
Marc

[Brad Conley]

Marc,
They can be anywhere from the week of production of the shell to about 6-8 weeks before. For my 70 GSX, the trim tag date is 09A (1st week of September, 1969) and the heads are dated H-15 (August 15, 1969).

There may be exceptions to this general rule of thumb, but the heads would never be later than the date of production.

[Dan Healey]

I think the smaller the part, the odds are much greater to have a manufacture date beyond the 2 month maximum. I recall seeing a date 9 months prior to my build date on the aluminum alternator bracket (without A/C), of course I'm not the original owner, so there is a chance it was replaced prior to 1982, (but not likely). :Do No:

[Brad Conley]

Here's an interesting one for you that enjoy such things...the spark plug wires on my Skyhawk are original. The long wires are date coded 1Q74 (first quarter 1974) and the short wires are date coded 3Q74 (3rd quarter 1974). The car was built November 1974.

I guess they had a lot of long wires and ran "short" on the short ones... :Do No: