Thanks Nick. I have an adjustable panhard bar,and the car has the original F41 rear sway set up. I'm wanting a set of Vintage silver 15 x 8 Torque Thrust D wheels with a 4 to 4.5 backspacing,but I dont think they make that backspacing anymore. All I've been able to locate on American racing site is 15 X 8.5 with 3.75 back spacing,,I fear those will rub on the wheelhouse lip. Open to any suggestion though,and thanks to you, Nick, and the others who have provided info to this question. Not sure what I'm gonna do.

275-60-R15 is a big tire with 8.5 inch wheels. They could rub the inner fender. Adjust Your panhard bar to center the wheels. I used air shocks or load leveler shocks with springs to raise the back. 255 is a better size. The 69 B body has less clearence than a 68 wheel well. Of course if You already ordered the tires try them. NICK L72

I have 15" X 8" Torque Thrust D wheels with 4 1/2" backspacing and 275/60/15 tires on the rear of my '68. They fit great with no clearance issues.
Chad