Tire and Rim Dilemma

I have 15 x7`s on my 68 Barracuda with 4.5 backspacing. I`m using a 255/60- 15 tire with at least 1.25 inches to spare before I come close to the lip. Evidently your wheelwells are not as deep as the Barracudas, but you should be able to get a 255/60 in there without a lot of trouble, if you get the backspacing right.