I run 275 60 R15's on my '68 Barracuda fastback. It has Superstock springs. I could for certain fit 285's and likely 295's. 295's are only 1/4 inch wider, on both the inside and outside. Check out my car in my garage for pictures.
295 60 d15 , 68 fastback , 3/4'' offset spring hangars , front of fender well lengthened to the inner structure/stock contour-------- car is now lower , tire is up in fenderwell about an inch.