The MV Agusta 350 6 cilindri (MV Agusta 350 6-cylinder) was a prototype racing motorcycle built by the Varese company MV Agusta in 1957, for the 350 cc class of the FIM Motorcycle World Championship. The project was resurrected in 1968. Neither version was ever used in a race. The only surviving model is now in the MV Agusta factory museum. 1957 prototype Background MV Agusta had won the championship in the 500, 250 and 125 cc classes of the 1956 season. However, the 1957 season promised stiff competition, especially in the premier 500 class, where the Moto Guzzi V8 and the Gilera 500 4C had shown great potential. Undecided whether to go down the road of evolutionary refinement, as Gilera had, or innovation, like the Moto Guzzi, Count Agusta opted for a dual strategy that included the development of the victorious "500 4C" and, simultaneously, the commissioning of a new multi-cylinder engine that could produce higher revs and therefore outperform the proven four-cylinder. The outline of the project was conceived in the first months of 1956. Sporting director Nello Pagani was in charge of the project, which was carried out with the maximum secrecy. The engine had cylinders and cylinder head made of light alloy was equipped with separate cylinders with cast iron liners. Like the four-cylinder models it featured double overhead camshafts with two valves per cylinder. Six Dell'Orto SS26A carburettors were used. The frame was derived from the "500 4C": a double cradle in steel tubes, with detachable front tubes to facilitate assembly and maintenance. 350 cc version The 350 cc was a logical development from the 500 cc version. The machine provided enough power, but this did not outweigh the extra weight. The twin camshaft engine (the camshafts were driven by spur gears between cylinders 3 and 4) had two valves per cylinder. The bore was 44 mm and the stroke 38.25 mm. Six Dell'Orto carburetor supplied the mixture which was ignited from a Lucas magneto. A Double cradle frame was used, the lower tubes of which could be detached for easy removal of the engine. In 1957, the six-cylinder 350 cc was used only once, in practice for the 1957 Grand Prix of Nations in Monza by Nello Pagani. After Moto Guzzi, Gilera and Mondial retired from racing at the end of the 1957 season, the project was shelved. 1968 prototype Background The remarkable success