During the late 1930s, the BMW 328 as a series vehicle dominated the two-litre class in motor sport. The engine design was particularly exciting: Engine designers took the proven engine block used for the 2 litre engine and designed a new cylinder head made of aluminium alloy for it. The inlet valves were operated from the side camshaft using push rods and rocker arms, the exhaust valves were operated using reversing levers and horizontal push rods. This configuration enabled the engine to achieve power in excess of 80 hp -E5 with power of as much as 130 hp being generated in the racing version.