I bought my 65 Barracuda last summer and it had 15" tires and wheels on it. It had 215-65-15's on the front and 235-60-15's on the rear. The fronts were very tight in the wheel well and they would rub the fender lip once in awhile. I researched and decided to go smaller and narrower on the front 195-60-15 and taller in the rear but not wider 235-70-15. I had them mounted and balanced last week and put them on over the weekend. WOW!!! I really like the way they changed the stance of the car and no more rubbing. The rears fill the wheel well and I don't think I could've fit a bigger tire in there without tubbing it.
Here's the before and after
Here's the before and after