1959 9400 trucks 10000-14000 GVW 235-6 Cyl. Or 283-8 Cyl.
9413 (4103 US) chassis & Cab 132.5 wheelbase Curb weight 4465
9443 (4403 US) chassis & Cab 156.5 wheelbase Curb weight 4610
You will have to add a little weight for the 2 speed rear and the auxiliary springs for max. GVW
If it has a 261-6 then someone add it. Check the chassis serial plate it will show the engine size.