[patrickt]

Originally Posted by Kit Coyle

Pin drive. I assume a standard 7.5" pin drive wheel had a 2" slice cut out of
the center and welded back up again to make a "narrowed" 5.5" wheel. I
believe there are wheel services that will do that to cast wheels. Put an
appropriate sized tire on and you have a working spare. Replica hold down
fittings with a copy of the original AC aluminum nut are available at reasonable
cost.

Excellent.