My KB-5 has those wheels and tires, supposed to be 1.5 ton, don't have GVW handy. KB-5's also came w/ 700 X 20's. 19.5's might be a bit small for looks, 22'5's might not fit the wheel wells properly, would give better road speed, however.

Highest ring and pinion ratio was 5.38 for 17" tires, no parts, I replaced the IHC rear axle w/ a Dana 70, 3.73 ratio, from a Ford, correct spring spacing, made new top shock brackets, made wheel adapters to use original wheels(17".) Good radio for direct trans. w/ 345 engine, a little high for heavy load(trailer.) Can drive 70 on highway, 60 more comfortable, stock front brakes.

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.