I've said before that I did a flip by cuttin off my spring pad, rewelding it to the bottom and put the spring under the axle.
Frame NEVER hit and I towed my racecar to the track everyweekend. I didnt have to notch my frame untill I got my 22's and had to do that to get the ride hieght I wanted. And even then I didnt do a serious notch. A 4" piece of pipe cut longways to make a c then notched and welded.