Tire sidewall clearance

Not sure which of the rides you're asking about. Like that '66 BTW. Is it a track car or a strip car?

I was interested in running 255/60-15 on the Demon. I put an old pair of these on 15 x 7 cop car rims, 4½" BS. In the rear, they were easily less than ½" from the spring on the inside. No problem with clearance from the wheel well opening, but they would be into the wheel well with about 2½ of spring deflection.

Stumped with this trial, I called Stockton Wheel. They suggested a max tire package of 235/60-15 (26.1" tall, section width 9½" on a 7" wide rim). These are a little snug in front, but OK at the rear. Every once in a while, I'll bounce a tire off the inside of a wheel well. I can only imagine how often it would happen with a 255/60-15.