The Mefistofele was created by Eldridge in 1923 by combining two pre-existing Fiat components. The chassis came from the 1908 Fiat SB4, a racing car that dated from the pre-war grand prix era, while the engine was sourced from the Fiat A.12, a six-cylinder aeroplane unit displacing 21.7 litres (21,706 cc) and producing approximately 320 PS (235 kW; 316 bhp). Mating such an enormous powerplant to a comparatively slender racing chassis produced a car of extreme proportions, and it was reportedly "baptised" with its demonic name by Frenchmen who witnessed its first test runs, struck by the volume of noise from the unsilenced exhaust.
On 12 July 1924, Ernest Eldridge drove the Mefistofele to a World Land Speed Record at Arpajon, France, achieving 234.98 km/h (146.0 mph). Arpajon, a straight road south of Paris, had been a favoured venue for speed attempts in the early 1920s, hosting multiple record runs on its public tarmac. Eldridge's run represented both the peak and the end of this practice: the Mefistofele's 1924 record was the last ever set on a public road, as regulations and venue preferences subsequently shifted to closed circuits and purpose-built courses such as Brooklands, Pendine Sands, and eventually the Bonneville Salt Flats.
The record stood only briefly in absolute terms as the land speed record era was intensely competitive in the 1920s, but its place in history was secured not merely by the speed achieved but by the circumstances: a privately built special, using repurposed aero and racing hardware, driven at maximum effort along an ordinary French road.
The Mefistofele survived the decades following its record run and underwent a restoration process lasting approximately five years. The restoration required sourcing another example of the same Fiat A.12 aero engine — itself a rare artefact by that point — to return the car to running condition. In 2011 the restored Mefistofele made a celebrated public appearance at the Goodwood Festival of Speed, where it was demonstrated to audiences encountering it largely for the first time, its reputation having long preceded it in the historical literature on land speed record cars.
The car represents a significant early chapter in the Italian motorsport story. Fiat was one of the dominant forces in grand prix racing during the late pre-war and early post-war period, and the Mefistofele, though a private venture rather than a works effort, drew directly on the engineering heritage of that programme. Its combination of aero engine power and stripped racing chassis anticipated the approach that would define many later record cars of the late 1920s and 1930s.
The name Mefistofele remains one of the most recognisable in the history of speed record attempts, appearing regularly in accounts of the land speed record's development and in the catalogues of major concours events and automotive museums.