To gain efficiency and performance Henry Parohl installed 4 valves in the head of this engine in the 1960s. The two rocker-arm shafts are controlled by a single camshaft behind, and at the base of the cylinder. Gasoline is gravity fed into the float bowl (of carburetor), which maintains a constant pressure and steady volume of fuel available to the carburetor. Lubrication is accomplished by gravity from a small transparent reservoir that the operator must fill before running the engine. It is located behind the fuel tank and slowly meters oil from the reservoir into the engine for lubrication during operation. The rocker-arms and shafts must be manually lubricated before running the engine. Typically, model air-cooled engines are designed for aircraft, but Parohl fitted this one with a flywheel and rope-start pulley for a model powerboat or automobile. The engine is 9”-long, 9”-wide, and 10”-high.