Paul,
Welcome to Stovebolt.com.
There is no 3600 model GMC ("52 GMC 3600").
You might be referring to a GMC 150 series (3/4 ton truck)?
There is a GMC 102 series 1/2 ton longbed (same size bed in a 150 series GMC and in a 3600 Chevrolet).
What 6-cylinder engines are you referring to?
GMC (228, 248, 270, 302) or Chevrolet engines (216, 235, 261) - you might want to designate make and cubic inches.
Ok, my 52 GMC is a 3/4 ton long bed whichever model number it may be. I thought that I had seen 3600 on one of the old registration cards so that is what I have been calling it.
As for which 6 cylinder engine I am referring to. . . that is what I am trying to get advice on as to which one will be best for me to put into the 1950 GMC for ease of repairing/rebuilding it to put into the truck for for future repairs.