The "directive" for VIN derivitives on blocks and 4-spds began in '62. All the Corvettes have them (one plant) but the practice was sporadic at the Passenger plants. I'm almost certain it was not an inspected procedure, therefore it was easily by-passed by lazy line workers. It was still sporadic through '64! So, unfortunately if you look at a hi-perf 62-3-4 car and it does not have the VIN derivitive, it does not mean it's not the original motor or trans! And even when they did stamp it, there was no "set" formality, meaning some had the plant letter designation preceeding the sequence number and some did not. There were a lot of variations in the font sizes and character styles, and some were gang stamped and many were individually stamped.
I have a pretty good collection of original examples, so if you ever run into one you're not sure of, just run it by me. I can probably tell you if it's real or not.
Verne
