I'm not sure of the background on the engine to the far left. Same goes for the "blue" engine with the radiator. The green one to the left is a Vaughn (castings by DeBolt). The white one is a Gray with castings from Cooper Tool in Alabama or Louisana ... can't remember which. This is a flyweight governed hit-n-miss engine with 1.850 bore and about 2-1/4" stroke. The piston has Honda motorcycle rings. Excellent workmanship on these engines.