Rear Versus Front Tire Widths
Ima thinking you don't have Factory Mopar wheels.
The Mopar wheels are all ZERO offset, AFAIK.
The factory steel wheels for a 67 Barracuda would be a
14 x 5, which measure 6 inches outside to outside, so would have a backspace of 3inches. From the Factory, it would have worn a D78-14 or a 6.95/78-14. That's a mighty skinny tire.
Every wheel has a particular size of tire, that will last the longest, at a factory specified tire pressure.
You can usually get away with one size either way.
Just so you know, on my 68 Barracuda ;
>on the back are 295/50-15s, on 10" aftermarket wheels, with a 4.5 backspace = a one inch offset.
>on the front are 235/60-14s on 7.5" aftermarket wheels, with a 3.75 backspace = a half inch offset.
>With these wheels, the treads are inside the tubs, but, the rearend was narrowed to make it happen.