Looks like VW or Porsche rear brake drums. Maybe the engine behind his head in front of the transaxle. Quite interesting.
In the worthless information department: This truck/bus is from the now gone Sunflower Ordinance Works which was just east of Lawrence, KS. I would surmise that the name came from the Kansas state flower. The plant closed in 1993 and was a huge sprawling thing. The truck/bus was used to ferry employees from far flung parking lots to the doors. The old Firestone Tire building is at 2001 Grand Ave. Kansas City, MO. It is no longer called the Firestone building and is used as a wedding venue. The neon sign has been replaced with the new owner's name.
Cause he`s the one who lifted that chevy and slammed it on the ford and just showing off his physique.