I have run a 235/60 x 14 tire on the back of my 65 Barracuda, and it did fit, but I agree with the Professor that a 235 is a tad wide for a stock 14 inch ralley wheel (really 14 x 5.5, not 14 x 6). Still, I never had any problem with that setup except when I had a couple of passengers in the back seat and then it would rub slightly on turns.
Now run 15 x 7 SBP Cragars with 225/60 R 15s. They have more offset and actually fit better than the 14 inch ralleys.
But even 15 inchers don't give you much of a selection of genuine high performance tires these days.