Wheel/Tire help for 68 notchback barracuda
15x7 rims with 4.25 backspace is optimum. You can go 215/60/15 in the front and 225/60/15 in the rear or 235/60/15.
You can get 15x7 rims with 4.25 backspace in ralley rims with your 5 on 4" lug pattern made by Wheel Vintiques. Try
www.SummitRacing.com but may have to call for the 5 on 4" lug pattern.
A lot of the people running wider rear tires have new springs that raise the back and give them more clearance. I'll assume you rear leaf spring are original.
These are 15x7 rims with 4.25" backspacing and 225/60/15 front tires and 225/60/15 rear tires on my Barracuda at one time.