I have a 68 Fastback that I need to put new tires on. Currently my car has Goodyear Polyglass GT F60-15's on it that are like brand new. I want to upgrade to radials. My rims are 15x7 and with these tires the wheel wells are filled with tire and it looks great. I want that look again with the radials but I definitly do not want them to rub the fenders. What size tires do you recommend?