Slicks with stock spring location? (I know I'm crazy)

I have a 68 Dart with 275/60/15 on 15X 7 (I think) rallye wheels. Axle moved back about 1" on springs & inner fender lip trimmed, & 11X2 drums. I know tire profile will be different though. I'm replacing wheelhouses and Quarters & don't want to sawz-all this time around. Probably go with a fender roll, & drop down to a 255 or 245 if need be.