this almost matched the performance of the old tre, which had reached the limit of its development. arturo magni, race director and chief engineer at mv, failed to achieve the necessary reliability with the smaller, lighter engine. the helicopter division of agusta under dr. bocchi, who had previously developed twelve-cylinder engines for lamborghini and ferrari, was asked for help. bocchi continued to develop the engine. the camshaft was driven via gears, previously on the side of the cylinder block, was now arranged between cylinders 2 and 3 as in the previous engines. the four-cylinder had a width of 40 cm and a dry weight of 55 kg. the light metal cylinders were cast in a single block. the one piece cast cylinder head had pent-roof shaped combustion chambers. the two inlet valves were 20.5 mm and two outlet valves 16 mm diameter. the valves were operated by bucket tappets and closed with double nested coil springs, the valve angle was 55 degrees. bore was increased to 58 mm and stroke to 47 mm to give a 497 cc displacement.