15x8 rallys on 74 duster

Where did you get the 15x8 rallys with 4 1/4" backspace?
The only thing I found,is wheel vintiques 15x8 w/ 4 1/2" backspace from summit. My 15x7's w/4 1/4" clear the springs with the 1/4" spacer.
I have 14" rallys on front, and want to move the 15x7's to the front.
Then put 15x8's on the rear. I just want to make sure they clear the inner wheel wells before I order them.