Help. I am looking for 1966 Ford F-350 rims 16" 6 holes 7.25 bolt pattern.?

I own a 1966 Ford F-350. The rims on the tires rusted out and I can't find replacement rims for this truck. Does anybody has any ideas on what I can do? Is there any other model rims that fit my truck? I bought this truck brand new and it means a lot to the family.