65 dart, fender well headers tire issues...

I used a 23 x 5.0-15 goodyear frontrunner on a 15x4 centerline prostock on my cortina. Strangely, centerline offered two different backspace on the 15x4 prostock. It is a pro tree car, and it has a tiny wheel well.
My opel has fenderwell headers, but a firestone 165 r x 15 (80) fits on a 15x4 rocket front.
My 62 has one header tube thru the wheelwell, and a 235/70x15 rubs on one side, 165 80 x15 on 15x3 1/2 fits fine.