255-60's will fit on 15x7's on a 70 Swinger

Thank you.
The 73's don't have the skirt, but I did push the bumper back about 1 inch.
I was reading about it last night I have the original piece but it is all ugly and they don't reproduce it. So from what I read everyone drills out the bumper shocks and pushes them back and welds them in place . I was just wondering how this is actually done? From the looks of my shocks they are not even anyways one side looks longer than the other.