I'd go with LT215/85R-16 Michelins,or Pirellis if you can find 'em. Very close to same size as stock,you can find some that even have the old timey looks too. They're not "too heavy for a little 1/2 ton AD truck",as it IS a truck,and these ARE Light Truck(LT) tires.
Start running them at close to their max pressure and back the pressure down a little at a time until you're satisfied with the ride and handling.
If you decide they ride too rough,you can probably run them at 75% of their rated max. pressure,unloaded.Of course,inflate them to max if you need to haul gravel or firewood.
Speed

1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck