Jim, since I drove the car 95% of it's 178,000 mile life on either Firestone Wide Ovals or Goodyear Polyglass, I have no basis for comparison. It was always, "the way it handles". I do it now for originality look and never push it too hard anymore because I want it to last past my lifetime. I drove it on it's factory original KM option rayon radials option but I neither remember back 37 years ago or believe that the 60's radial technology had any relationship to today's tires.
I've driven a few hundred cars in my lifetime and my '68 has it's unique characteristics that no other car has had.
If we lived closer, I'd let you put them on your car for a test drive.
I do it now for originality look and never push it too hard anymore because I want it to last past my lifetime. I drove it on it's factory original KM option rayon radials option but I neither remember back 37 years ago or believe that the 60's radial technology had any relationship to today's tires. 
