"Are you saying the engine codes were hand stamped at the factory . . "
I do not think that they were stamped at the engine factory/plant (but, I have no documentation).
Chevrolet engines were made at one of two different engine factories/plants (Tonawanda, NY or Flint, MI) and then shipped to one of the 10 truck assembly plants.
My guess is the engine ID was stamped one-truck-at-a-time at one of the 10 truck assembly plants.
Or, at least some of the stamping was done at the truck assembly plant.
Some years have date-of-vehicle assembly stamped in the engine serial number (depending on the year).
This could not have been done at the engine plant.
Also, the size of truck was sometimes indicated on the engine serial number.
My bet/understanding is that this was done/stamped at the truck assembly plant?
One joke I have seen posted was that the lines of characters were shakier on Friday afternoon, after a few beers at lunch.
My speculations are based on what people have posted here and on OldGMCtrucks.com. I have no documentation supporting where the engine ID stamping was done.
Do you have documentation that the Engine Serial Numbers (complete engine identification code) stamping was done at the engine assembly plant?
I agree that some stampings look like they were done by a machine . . . . but, some stampings have looked like they might have been done by a drunken sailor (my apologies to Navy Veterans).
