on my 71, B78 14" Good Year Polyglass. Still have original spare... so skinny it looks like the original donut!
I believe I still have an original spare from a '74. I think it is a Goodyear. I will take a look and see.
My Sprint came with Goodyear Polyglass GT tires in a D70-14 whitewall. I still have one of the originals too.
My Stallion came with D 70 14's and the make was Firestone, yes, the infamous Firestone 500.. at that time the largest tire recall ever. And I had 2 cars that had them with a 76 stang cobra II. They replaced them with Firestone 721's. I dont have any of my original tires, think they got lost in the rare midwest typhoon of 78. Dan