275/60 on a Demon?

I have 15x8s with 275/60/15s on my 71 duster and the car sits low with the tires in the wheel wells.I had to flatten out the buldge on the outside wheel because the tires would touch when hitting a large bump.Its a nice mod to do since it really increases the room and theres no need to worry about tire growth at the track.Heres the only pic I have,it sits pretty low.