After World War I Hispano-Suiza returned to automobile engine design and, in 1919, introduced the H6, earning them a reputation even greater than that of Rolls-Royce in England. Indeed, Rolls-Royce featured many Hispano-Suiza patented features, under licence. Most notably, Rolls-Royce used for many years the famed Hispano-Suiza power brakes, reputedly the best in the world, which used the torque generated by a drum brake mounted on the transmission shaft to power those on the wheels.
The H6 featured an inline 6 cylinder overhead camshaft engine based on the features of the V8 aluminium World War I aero engine and a body by Hibbard & Darrin. Through the 1920s and into the 1930s, they built a series of luxury cars of increasing refinement. In fact, the 1930s V-12 car engine reverted to pushrod valve actuation to achieve even less engine noise.
During this time, Hispano-Suiza released the 37.2 Hispano-Suiza car built at the Hispano works in Paris.
In 1923 the French arm of Hispano-Suiza was incorporated as the Societé Française Hispano-Suiza, the Spanish parent company subscribing for 71% of the share capital. From then on, the French company gained increased an degree of financial independence, while the technical links were always kept strong. The mascot statuette atop the radiator used by this firm after World War I was the stork of the province of Alsace, taken from the squadron emblem painted on the side of the aircraft of the renowned World War I French ace (and Hispano-Suiza customer) Georges Guynemer, which was powered by a Hispano-Suiza engine. At the time, this was an emblem of revanchism.
In 1925, Carlos Ballester obtained permission to represent the Hispano-Suiza brand in Argentina. The agreement consisted of a phase in which the chassis were imported, followed by complete domestic production in Argentina. Thus “ Hispano-Argentina, Fábrica de Automóviles S. A. (HAFDASA)" was born, destined to the production of Hispano-Suiza motors and automobiles, and also the production of spare parts for other car, truck, and bus manufacturers.
A fictional example of a Hispano-Suiza appears in the P.G. Wodehouse "Blandings Castle" stories; the family drove or rather were driven in a Hispano-Suiza (H6), rather than, say, a Rolls-Royce. Also in the Agatha Christie novel The Seven Dials Mystery the main character, Lady Eileen "Bundle" Brent, drives herself about in her "Hispano".
