[Jack21]

Went through a similar exercise trying to explain to a DMV inspector how to determine the "Year" of the engine using Ford part numbers and block casting codes. Had an old Motors Manual (similar to Chilton service guides today) that had part number references back to the mid '60's. Flipping through the pages, I explained how C5 = '65, C6 = '66 etc., for year of manufacture or service.

Might have to resort to this with UK DMV.