The Mercedes-Benz 300 SLR racing car was based on the Mercedes-Benz W196 Formula One car.
The 300 SLR, internally designated W196S, was developed for the 1955 World Sportscar Championship from the W196R Grand Prix machine. Mercedes enlarged the W196’s 2.5-litre straight-eight engine to roughly 3.0 litres and adapted the car for endurance racing.
The sports racer retained major W196 features, including its space-frame chassis, front-mid-mounted straight-eight layout, direct fuel injection and desmodromic valve gear. However, it was not simply a two-seat W196: Mercedes added road-racing equipment, changed the cockpit for two occupants and fitted headlights and storage provisions.
A common mix-up is the Mercedes-Benz 300 SL road car, whose name and styling association can suggest a connection. The 300 SLR was instead a competition derivative of the W196. It won the 1955 Mille Miglia with Stirling Moss and Denis Jenkinson, but Mercedes withdrew from racing after the catastrophic Le Mans crash that year.