65-70 leaf spring date code reading

[cbrown]

Can we discuss the date codes on 65-70 shelbys  and  mustangs to clarify things?

I have early car samples   which are julian dated then the month then year.    Why did they do julian date and the month ?  Then number should tell you which month it is.. 

I have later 68 leaf spring that I do not understand  which    reads     C7ZA  5556 AM  then the date is 85K      what is 85K?   this is on an original  gt500KR..

  then have 69 leaf S9MS that is back to julian then year   no letter designating  month..

chris

[J_Speegle]

K would be the plant/supplier from my understanding not the month - the number would be the Julian date or 85th day of the year . Being either a standard or leap year.  This pattern seems to line up well with a fair number of dates I've collected from cars over the last few decades

This info is in a date decoding article in the Library of one of the other sites you belong to    Need to update it and expand it with more info - just need the time

[cbrown]

That sheds some light on  things..  So 68 springs no year designation?   

chris

[J_Speegle]

That sheds some light on  things..  So 68 springs no year designation?   

Depends on the supplier it appears. Have some with a number (year) as the last digit in the bottom line and on others no number (year) as the last stamp


There are some that were installed in 68 (no Shelbys that I've found) where the supplier used a pattern such as plant followed by a dash and then a single numbered year followed by month it was stamped.   Example G1-8C. So those are not day specific as the other supplier would be

Seems like there were a bunch of suppliers but it also depended on which plant used which supplier on a regular basis