The red #6 is the 6th one I built. #'s 3,4,5 &6 were all similar in that the bodies were hand hammered over a wooden plug. The frames were waterjet cut from 6061 1/2" aluminum. All other pieces were made in the shop. I made up molds for the tires and had them vulcanised at a local rubber shop. They are the same as the "Dooling" cars.
The black car has a wooden body on an aluminum channel frame. It is built just like a full size dirt car of its era, complete with steering, which can be locked for tether running. I built it from a print in Robert Ames' "Vintage Miniature Racing Cars" that I purchased in the early 80's.