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 V8 engine of work under Les Maddock and Colin Weston, the first result of which was the N80, a 4-valve, double overhead camshaft, 5.0 litre V8. This successfully ran first stage 1000 hours testing straight off the drawing board without incident. Subsequently, the marketing brief foresaw the requirement for a higher capacity version and the N81, 6.0 litre version, was designed. The project was stopped around 1991 with further development of the L410 engine that enabled emissions requirements to be met using a pre-catalyst assembly at substantially lower investment. Rolls-Royce V8 engine In the history of Rolls-Royce automobiles, only two distinct series