Hi there Rich! Looks like you have a great truck!
I'm pretty sure, too, that those aren't the stock rims. A '63 Chevy that I got the rearend out of had almost the exact same rims, and they weren't stock...
I keep 235/75 r15 tires on my '61. Of course my truck has 15 inch wheels, and the rims are in no way stock, haha!