Thanks for clarifying Carsten, so it's one of the big mysteries. We need Doug over here, I'll email him a link to this thread.
Y codes....
there are few absolutes when it comes to tags but here's one:
What was coded, when it was coded and even where it was coded differed from year to year, plant to plant and even during the model year. "Early" tags can code differently than 'late' tags.
Regarding 69 and later cars: some plants are very consistent with "Y" codes and some were not. As Carsten said, you find very few Y codes on '69 STL tags. Some plants, like '70 Hamtramck, most all cars have a Y code for country of sale (Y05, Y07, Y09). So Y codes may be found on some tags and not on others. It depends on the plant, the time of year and the type of Y code used. You cannot draw comparisons between what the STL plant did in '69 and apply the same coding structures and rules to the '70 Belvedere plant. It doesn't work that way.
Sometimes you can relate the Y code to the Vehicle Order Number (VON). Sometimes the VON tells you the Y code. Again, it just depends on the year and the plant.
Learning the nuances of the different years and plants takes a lot of study of a significant sample size to learn what was done and when.
One of the reasons I started hanging out here, besides the stellar personalities, was to learn about C body tags and how Belvedere, Jefferson and Newark coded tags through the years. C body tags are harder to learn as there are fewer of them to find and compare between the various plants. It appears to be a part of the hobby that just does not interest C body owners so there is less sharing and comparing than the other body styles so one has to do a lot of self learning.
