67-69 barracuda front tire width
I don't know if there is a direct conversion. The old system was based on actual treadwidth, while the new is based on a section width. Well, I mean I guess you could back-calculate but IDK how accurate that might be.
I also remember Es on the front and Gs were as big as would fit in the back of my 70Dart. Seven sets of rear tires in four summers; 2or3 summers of which were in highschool,lol. And the front burned off all the Es. Daymn that 340!