ModelAMike1930,
Try this, go to Steve Pluckers website
http://www.plucks329s.org/
There you will find "Additional Studies" and within this you will find
"Letters, Numbers, and Codes"
"This study addresses questions regarding the various production numbers found on the Model A/AA".
Here is a link to the PDF file:
http://www.plucks329s.org/pdf/studie...ND%20CODES.pdf
Model A engine numbers are the origin of the number stamped onto the frame.
Darryl in Fairbanks
Thanks to Steve Plucker for the Research and Information.