Wikipedia
The FIAT Mefistofele (sometimes known simply as Mefistofele) is a one-off racing car created by Ernest Eldridge by combining a Fiat racing car and aeroplane engine in 1923. The name is from the demon of the same name, and the name refers to the infernal noise emitted from the unmuffled engine, and it was "Baptised" by the Frenchmen.
Eldridge broke the World Land Speed Record on 12 July 1924 with the Mephistopheles, by driving at in Arpajon, France.
The Mephistopheles was created by combining the chassis of the 1908 Fiat SB4 with a 6-cylinder, 21.7 litre (21706 cc) Fiat A.12 aeroplane engine producing .
The engine named Fiat A.12 is a six-cylinder liquid-cooled in-line engine with a bore of 160 mm and a stroke of 180 mm, giving a capacity of 21,7 litre, with variants producing between 245 and 300 horsepower at 1,700 rpm. The A.12 was a rather large aero engine at the time and its dimensions were more typical of a marine engine, but it was efficient and reliable. No doubt Fiat's experience with large racing engines contributed to its success. A total of 13,260 A.12s were produced between 1916 and 1919.