[blucar]

The standard 1/2 ton wheel, '40-56 is a 16 x 4.5, 5 on 5.5 bolt pattern, inside hub cap knobs. The standard tire is 600 x 16, 4 ply, the HD option is 650 x 16, 6 ply.
A modern option for the F-1/F100 series is the '57-66 F100 15" wheel, which is a 6" or 6.5" wheel with inside hub cap knobs, therefore the stock hub caps fit.
A good tire size for the 15" wheel is a 235/75R15, it is a 28" tire, same as a 600x16, just a little fatter. It is a good idea to install a hydraulic steering dampener on the tie rod when radial tires are used on the front end of a solid I beam axle pickup.