[Steve Ciccalone]

I looked at two Ford Script SP straight pole coils yesterday. One was stamped "3 Y" in the usual font as Will mentioned. Counting from "L" in 1931 this would make it a March 1941 coil, assuming the "O, Q and V" were not used. The second was "B 7". The "B" was a significantly larger font size than the "Y" and was a much shallower stamping. Perhaps after reaching Z, the code simply reverted to "A", but in a different font.

I assume there was a manufacturers' association for makers of automotive electrical equipment that established standards like SAE and created the date codes as it seems the same on all the different brands of A coils I've seen.