The Maserati 300S was a racing car produced by Maserati of Italy between 1955 and 1958 to compete in the FIA's World Sportscar Championship. Twenty-six examples were produced.
Background
The 3.0-litre (approx 245 bhp at 6200 rpm) engine was based on the Straight-6 design of the Maserati 250F and incorporated a lengthened stroke developed by Vittorio Bellentani to increase the capacity from the original 2.5-litres. The compression ratio was reduced from 12:1 to 9.5:1, partly due to the FIA regulations requiring the engine to be run on road car fuel. It used three Weber carburettors, initially 42DCO3, later 45DCO3. A trellis structure was used instead of the tubular one of the 250F, and the aluminium body was by Medardo Fantuzzi. The brakes were the same as the 250F, precisely machined alloy drums with extensive finning. The suspension was also of the same design as the 250F but with some strengthening to cope with the rougher tracks and road surfaces encountered in WSC racing. New features for the 300S included the incorporation of a De Dion type rear axle, a transverse four-speed gearbox and two chain driven camshafts.[1][2]