30in tall tire on 75 duster

I have a 94" circumference Hoosier 9" radial on my Dart Sport and the front and rear lower ends of the wheelwell opening are cut for clearance. (That works out to about 29.5".) But I don't remember how much they were cut.

When you do clearance them, remember that particularly bias ply slicks will grow on the top end. Radial slicks do, but very little. The wider the rim and more air pressure, the less any tire will grow.