Suggested wheel size for rear

Oh man,,,,sorry !
I knew I was tired,,,lol .

It’s a 73 Swinger .

Tommy
I have 17 x 8’s under the rear of my ‘73 Swinger, no sweat. I have 4 1/2” of backspace with a stock 7.25” rear. I have a 245/50 on it and the tire causes a few rubs occasionally. That could be a result of the car being lowered a considerable amount though. Hotchkis leaf springs with their provided front hangers.