I'm running a 64 Camino with 28x9 slicks in factory fenders, trimmed on the outer edges, on 15x8 wheels with 5" backspace. Section width on my tires is about 10.75" and they don't rub. I run 215/75/15 tires on the street with 15x6 wheels since I can't hook street tires anyway.
Devin