Thanks Gary. I come here too, there's just not as many truck issues here as on FTE.
Below is a picture of a '53/'54 F-350 single rear wheel. Looks like a dual, but it's a single. It is Ford #TAAA 1007A, made by Budd under their #65720. It is 17" x 5.5", has the 6 x 7.25" pattern, 5" of positive offset, and unfortunately has the Firestone RH-5° killer rim.
One replacement option, as Gary said, is a custom set built by Stockton Wheel, or other company, using the stock center discs. We've seen this done with similar wheels and know that the disc fits nicely into new tubeless 17" drop center rims.
Another option is to find a set of 17.5" x 5.25" tubeless wheels. Optional on F-350s 1956 to 1966. Ford #B6Y 1015A / Budd #71320 (6 hand holes) or 79120 (3 hand holes). Also used by Dodge and IHC 1956 to 1968 iirc. Picture below. A drawback here will be a shorter tire diameter. Your 7.50-17" is 34" tall where an 8-17.5" will be 32" or slightly less. Sometimes I know of sets available with wheel oriented friends, but do not right now.
