Rear Versus Front Tire Widths
On my 67 coupe, I'm running 15x8 Cragars (4.25 inch backspacing) on the rear with Nitto 275/60/15 radials; 15x7 Cragars on the front with 225/60/15 Falkens.
Chassis is stock height front and rear. The larger diameter rear tires raise the back end by about an inch.