Thanks for the reply Wayne. Mine is a 131.5 wheelbase. I failed to mention my GMC is Canadian T15 (it says so on the trucks I.D. plate) and I think the Canadian trucks have substantial differences. I found this document Canadian GMC info that shows "
T-15 BODY CODE P, S ¾ TO 1 TON 131½ IN. WHEELBASE. So, I think it is a 3/4 ton or 1 ton but I can't tell anything from that plate in my original post. Maybe if someone had a similar MVGW on their truck they could solve the mystery. For instance, my 46, GMC 1/2 ton has a Max gross weight of 4600 pounds. If the empty weight of it is 3000# (the weight of a 1937 112" WB pickup) then I figure the difference between those two weights would be the allowable payload. In this case, 1600#s = 1/2 ton. For the 131.5 WB 1937 panel, it weighs 4200# ( from the link Wayne gave, I added the chassis + cowl weight to the panel body weight to get 4200#) and has a MVGW of 6000 which = a payload of only 1800 pounds. Not much more than the 1/2 ton truck. Obviously I can't make sense of it.