I don't want to re-invent the wheel

My car is a 72 Demon with what I believe to be a 73 or 74 front disk system, single caliper.

The 15x6 with a 3.5 inch backspacing sounds about right. The tires I would be looking at would be a 70 profile. This is no corner carver, it likes a straight line. lol

Interesting comment on the rear back spacing. My current rear wheels are 15x8 with a 4 inch backspacing, tires are 275-60-15, so it does make sense that a 15x10 and a 6 inch backspacing would put the outer side of the tire, new tire will be 325-50-15, in the same place I have currently.

Jack