Ed,
I just talked to my Son, Sam. He is my go-to guy for all things Corvair. He says choices are VERY limited if your friend is stuck on the 1" whitewall, he might be stuck with the high priced Coker bias ply tires. Sam is running Maxxas MA1 185-80 X 13 with a whitewall width of a little more than 5/8". Coker sells this tire in a smaller size and Sam cautioned against buying them. They are available at Walmart and other places.
He said that if your friend drives his car, the bias ply tires would be a poor choice. You might already know all of this stuff, but I thought I should toss it out there, just in case.
I think Sam is Spyderman 64 on the Vair forums.
Mike