I have some 16" steel wheels off a '44 Dodge 1/2 ton pickup. The lug pattern is 5 on 4.5", same as '49-'65 Ford passenger. (and numerous Dodge passenger cars)
Wheels off any Plymouth, Dodge, DeSoto or Chrysler car, 1/2 ton van or pickup (except Imperial) before 1970 will fit. You can also use Ford, Hudson, Toyota pickup, Studebaker etc wheels but you will need to drill a hole for the locating pin, 5/16 or 3/8. The center register may not be the same size either. They came with left hand threads on the left side wheel nuts. Be careful, sometimes the hubs get swapped and you find LH threads on the right, or RH threads on the left.