Topic: Fan Clutch for 390, date code?

[mikelj5S230]

I am looking at my fan clutch (C7ZE-B) and on the inside plate area, around the spring, and see a faint stamp, with what looks like letters and numbers.  Is there a date code on these clutches, and if so what is the sequence?  Thanks.

[Bob Gaines]

I am looking at my fan clutch (C7ZE-B) and on the inside plate area, around the spring, and see a faint stamp, with what looks like letters and numbers.  Is there a date code on these clutches, and if so what is the sequence?  Thanks.

There are ink stamps sometimes on the front zinc dichromate plate but not always. I have seen originals that appeared to have a faint ink stamp and others that you could not tell anything was ever there.  I have had many NOS ones that had a ink stamp and other NOS ones that didn't or had one letter only. I am not aware the ink stamps are date related . FYI I have a NOS one I planed on putting on ebay next week for sale . Will have to check tomorrow to confirm if A or a B. PM me if interested and I will take some pics if a "B".

[mikelj5S230]

Well, I was looking at the 428CJ site here:   http://www.428cobrajet.org/id-fan-clutch

And saw, near the bottom, where they speculate the ink stamp is date related.

Now, if I use my Chevy/Corvette "spring type" Eaton fan clutch knowledge from '67-'68 (which look just like my '67 GT 390), had date stamps done at the Eaton factory, and this is how we decode them:

Example of a date code: A23F A=January, 23=Day of the Month F=1965.  The first letter in the date code is the Month... A=January B=February and so on, and the letter “I” was used and can sometimes be confused as the No. “1”.  The date is either one or 2 numbers (1-31).  The last letter was the year it was produced.  With this you need to know that the first year they were date coded was 1960 and that letter “A”... A=1960 B=1961 C=1962 D=1963 E=1964 F=1965 and so on.  Chevy also added the “Broadcast Code”, which was "CK" for a big block Corvette, and the small blocks were “CJ”, and these were also ink stamped on the inside of the clutch plate where the spring is.  Guess Ford did not add that.

So, if I decode the one on the CJ site of "A27J", I would get January 27, 1970. The "I23J" would be September 23, 1970.  But, the "181C" is a mystery.  The dating convention could have changed or not been totally consistent?