'72 C-10, 402, is there a way to tell....

[burb71]

On the engine block there is a code thats stamped on the block it has the date of the build, if not the day its at least the day before it rolled off the line.

Most everything on these trucks were date coded, from the floor carpet to the vinyl on the seats.
Most part date codes on the truck will range from 3 months before the truck was finished, the the latest date that I find is the stamped code on the motor