Rolls-Royce Merlin exhaust flow and waste-gates, meant that this option was rejected in favour of the two-stage supercharger. Fitted with the two-stage two-speed supercharger, the Merlin 60 series gained 300 horsepower (224 kW) at over the Merlin 45 series, at which altitude a Spitfire IX was nearly faster than a Spitfire V. The two-stage Merlin family was extended in 1943 with the Merlin 66 which had its supercharger geared for increased power ratings at low altitudes, and the Merlin 70 series that were designed to deliver increased power at high altitudes. While the design of the two-stage supercharger forged ahead, Rolls-Royce also
Rolls-Royce–Bentley L-series V8 engine Flying Spur and Continental models. The first engine of V8 configuration was developed in 1904 by the Marmon Motor Car Company in the United States. It was experimental, however, and did not find its way into a passenger vehicle. Rolls-Royce premiered the world's second V8 engine in 1905 for their Rolls-Royce V-8 Legalimit – governed not to exceed the legal speed limit in Britain at the time of . It was not a success, with only three made and just one sold, which was soon returned to the factory to be scrapped. It was another decade before Cadillac pioneered a