If there is a metal ID tag on the cab between the driver's door hinges, post that code.
Photos in earlier posts look like a 3100, but there is no side shot of the bed (the 3600 bed is longer than the 3100 bed).
6 lugs on 3100 wheels and 8 lugs on 3600 wheels.
Do front and rear wheels have 8 lugs?
The rear was swamped out with a 1968 chevelle, it has five
