Replacement for split rims on C60?

[D6c]

New to the forum, so this may be asked many times before.

I've got a '66 C60 that I use for a grain truck that has the original 20" split rims. Tires are getting pretty old so if I replace them it would be nice to change wheels too. I can still get one tire shop to work on the split rims, but they don't like it very much.

Found Accuride wheels (p/n 28160) that are 22.5", but the dealer quoted me $400 ea x 6....way more than the truck's worth.

Are there any later Chevy/GMC trucks that have tubeless wheels that will fit?
(10 hole, 8 3/4" Bolt circle, 6 1/4" bore...uses flat face flanged cap nut)