...
Mine? A Dana 80HD rear... and 19.5 tubeless radials plus spacer adapters for the front (the newer rims have a 1/4" bigger center hole).
Would have LOVED to have kept the original mongo rims & tires but...
You can have your old wheels bored to the 5.25" center hole, or find 20" wheels from a truck later than about 1955 as they had jumped from the 4.75" up to 5.25" center hole by then.
Grigg