Usually ran 2157015 or 2257015 up front.
Besides,with over 2 inches O.D. difference between the 2456015/2756015's, that would give the car too much of a front rake and more nose down--that is if you are after that look.

15x7 are a tight fit for the 275's tires and look like a bulging ballon.
The wheel vintiques 15X7 and 15x8 has 4.5" backspace
Hope this helps
Not much room out back for a 275...2556015 is best on a 15x7 rim