FIAT Mefistofele is a one-off racing car created by Ernest Eldridge by combining the chassis of the 1908 Fiat SB4 with a 6-cylinder, 21.7 litre (21706 cc) Fiat A.12 aeroplane engine producing 320 PS (235 kW; 316 bhp) in 1923.

Eldridge broke the World Land Speed Record in 1924 with the Mefistofele, by driving at 234.98 km/h (146.0 mph) in Arpajon, France.