30in tall tire on 75 duster

well if it's going to be a tight fit with a little trimming needed, then I will be fine as cutting up the car is not an issue. I'm not worried about making it factory correct. It's going to be a 90% race car 10% street car, so it's better to have the room for the slicks that I want, than to go with slicks that sort of work. As for the tool posted earlier that would work if I had an axle in the car, but we will be building a custom axle baised off of where the wheels and tires need to go. Since the car only has a 7.25 in it now, I am opting to drop in a dana60 in it's place and adding a 4 link. So the tool you provided will not work for what I need. It is a nice tool though good find.