Tires 1974 350
GR70-15 blackwalls were standard...white stripe or white letter in the same size were optional. They were probably either Goodyear or Firestone (or both) depending on availability.
Current size would be P225/70R15 which is equivalent to a GR70-15.
Current size would be P225/70R15 which is equivalent to a GR70-15.





