I need to replace the tires on the rear of my 67 GTO convertible pretty soon. I'm thinking of going from my 235 60 15s to 255 65 15s for a couple of reasons. It will fix my speedo, lower the revs while cruising, and give a little more traction I assume. I have 15x7 Rally 2 wheels and the current tires fit fine with no rubbing. I do have new springs and drag bags installed so will the 255s fit?