Rim and tire fitment question

str12-340 said
If you ordered a 7 inch wheel with the same backspacing then the extra 1/2 inch is on the outside of the wheel toward the wheel lip where you said you only had a 1/2 inch of clearance! I've never been able to fit 7 inch wheels on my 70 darts unless I moved the springs against the frame with a kit and then had the extra width on the inside of the wheel taking up the extra space that was made.

I ended up buying Wheel Vintiques Mopar Rallye rims. 15x7 with 4.25 backspacing with 255/60-15 in the back and 15x6 with 3.75 backspacing with 195/65-15 for the front. Plenty of clearance from tire to leaf spring, however, I did have to trim the inner fender lip about 1/4". There was room, but I felt a little more was better.