The eight-cylinder engine of the 300 SLR racing sports car distinguished itself from the Formula 1 engine by a displacement increased to 2,982 cc, two cylinder housings of cast aluminium rather than cast steel, and the reversed camshaft rotation. It generated up to 228 kW (310 hp) at 7,500 rpm. The compression ratio was only 1:9, so that normal premium petrol could be used in accordance with the rules for the world sports car championship. Mercedes-Benz also tested this engine in the W 196 R for a racing event, namely the non-formula race on 30 January 1955 in Buenos Aires, Argentina. In contrast to its later use in the 300 SLR, the compression ratio was increased to 1:11 on this occasion.