Stock car stuff. I had a pair of 15x 12 stamped made by Firestone back in the late 70's, weighed a ton. I think Bart still makes a wheel like those shown.
Search for circle track parts places, or the catalog shops. The new ones are significantly lighter, too. Gary
in the mid seventies there was a company called " grand national " , they look simalair to them , they were heaver than haidies
Bassett makes some but the holes are larger... Speedway sells them, but they are not DOT legal. I don't know if Basset will custom make a set...