I have a pic of a big yellow "5" next to the voltage regulator on a 1950 3100. 5 window? I don't know.
There is a factory photo of the engines on the assembly line with marks on the head and bell housing.
Some parts had the date inked stamped.
Another way to make it look factory is replicate the overspray on the bottom of the hood and cab. It's ugly but correct.
Dustin
