old cragars and a 72 swinger

Bolt the rim on and use a straight edge against the outside and check clearance both sides to fender and to springs in back. this will tell you the section width that will fit when the short side is doubled and added together with rim width. then search bfgs site for section width and find which tires are 1 inch narrower than your measurement and this will give you a half inch clearance from the fender well or spring in rear.