The 340 MM was developed directly from the Ferrari 340 Mexico, a car designed for the 1952 Carrera Panamericana. The Mexico used a 4.1-litre Lampredi V12 engine producing around 280 PS at 6,600 rpm, clothed in bodywork by Vignale to a design by Giovanni Michelotti. Four Mexico examples were built.
For the 340 MM, Ferrari shortened the wheelbase from 2,600 mm to 2,500 mm, retaining the same 4.1-litre Lampredi V12 with three Weber 40DCF carburettors producing 280 PS at 6,600 rpm and a maximum speed of approximately 282 km/h. The designation "MM" referenced the Mille Miglia, the gruelling Italian road race that was a primary target for the model.
Ten 340 MM examples were constructed, spread across three body styles: four Pinin Farina Berlinettas, two Touring Spyders, and four Vignale Spyders — the latter again styled by Michelotti. This diversity of coachwork reflected the standard practice of the era, with specialist Italian carrozzerie clothing Ferrari's racing chassis according to customer preference and factory specification.
The 340 MM's most celebrated result came at the 1953 Mille Miglia, where Giannino Marzotto drove a Vignale Spyder to outright victory, setting a new average speed record for the race. A second 340 MM finished fourth overall in the same event. Two additional 340 MMs were entered in Touring barchetta guise at the 1953 Mille Miglia but failed to finish.
The 340 MM's competition life was relatively brief but productive. Its performance placed it at the forefront of Ferrari's sports racing programme during the 1953 season, alongside the V12-engined 375 MM with which it shared mechanical lineage. The broader Ferrari sports car effort in 1953 — encompassing the 340 MM, 375 MM, and the new four-cylinder models — was sufficient to secure Ferrari the first-ever World Sportscar Championship.
As the 340 MM's career wound down, four examples were converted to 375 MM specification, upgrading the engine to the larger 4.5-litre unit. This conversion practice was common for Ferrari's racing hardware of the period, ensuring continued competitiveness for cars that remained structurally sound. The basic chassis architecture and suspension layout carried forward into subsequent models, with the 375 MM serving as the direct successor.
The Ferrari 340 MM occupies an important position in the lineage of Ferrari's early sports racing cars. As a transitional design between the 340 Mexico and the 375 MM, it demonstrated the versatility of the Lampredi V12 engine family and the adaptability of Ferrari's tubular spaceframe construction. Marzotto's victory at the 1953 Mille Miglia — achieved at a new record average speed — stands as the model's defining moment, securing its place in the history of Italian endurance racing.