your tire set up?

On what car? I am gonna assume your Dart Sport
I have on my 73 340 Duster 225-70-15 up front and 275-60-15
Wheels are Mirada CMX Wheels 15x7 with 4 1/4 Backspace (Just like Factory Cop Wheels)
a 225-70 is slightly shorter than a 275-60 by like a 1/2 inch

Needed a 1/4 inch spacer on the rear so the tire wouldnt rub on the front spring pack clamp