Spring relocation without mini tub?

71 Dart. Moved springs in and mini tub. I cut 3" off each side of rear-end. I am running 28"x12"x15" MT on 15"x10" 5.5" BS. I have about 3/4" to outer fender and 1 3/4" to inner fender/frame. If I could get another 1/2"- 3/4" space in there I could run 28"x15"x15" MT's. Good luck.