I do not think that they were stamped at the engine factory/plant (but, I have no documentation).
I disagree, the engines were stamped with a Serial Number, Plant, Year and Type codes at each factory, otherwise how would the assembly plant keep track the different engines types? The flywheels and bell housings were installed at the engine plant, so how would the Assembly plant know the difference between a Type "H" 235 and a Type "HE" 235 w/HD Clutch if they weren't marked?
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.
The date on the engine is the date it was assembled, not the date the truck was built. Engines built pre-1957 had serial numbers that would tell the Plant when they were built. Post 1956 the serial numbers were dropped and the plant stamped the Plant, Month, Day and Type. If you have evidence of a engine serial number showing the date the vehicle was built by Chevrolet, please share.
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?
The size of the truck the engine was built for was included in the "Type"...Type "X" was a 235 for the 1956 1/2 ton, an "XA" was for the 3/4 ton and a "XB" was for the 1-ton.
Do you have documentation that the Engine Serial Numbers (complete engine identification code) stamping was done at the engine assembly plant?
See attached picture taken from the "Heavy Duty Truck Identification Information" book dated February 1968. The print might be small, but it reads "The continuous engine serial number has been eliminated. The engine plant now stamps a source, production date and type on serial pad."
Mike B
