30x9x15 on a 68 dart

jefflock said
A buddy of mine that races at the same track runs 30x9x15 Hoosier radial drag tires on the back of his 68 Dart. The wheels are 10" wide with 5" backspacing. He runs stock suspension with the springs in the stock location and wheelwells are stock.
My point is I didn't they would fit but they do.
Is anyone else able to do this??
My 68 Dart is tight with 235x60x15 MT Drag Radials on 15x7 with 4.5 backspacing.

I bet that if you put a tape on the rear axle, it has been narrowed. On my 64, I had to narrow the axle almost 3 inches per side to fit 15x10's with 5" backspace (Same as your buddies). My 64 is not that much narrower (if at all) then that 68.

Thanks,
OldMoparsRule!