The definitive March car for the 1972 Formula 1 season was to be the 721X, designed on the basis of the 711 and 721. The basic idea was to redesign the entire weight distribution using a gearbox mounted between the engine and the rear axle. The concept could be valid (it was already used by Porsche and Alfa Romeo) but in March its success was heavily penalized by the behavior of the Goodyear tires, unsuitable for this solution. When it became clear that the 721X could not work, March reverted to the traditional scheme by designing the 721G, built in record time.