Bugatti Straight-8 (Type 41, 12.76L)

Straight-8 (SOHC, 3-valve)12.76 L (12,763 cc)Naturally aspirated1927–1933275–300 hp

Designed by Ettore Bugatti. One of the largest car engines ever built. Four were fitted per Bugatti Autorail railcar (800 hp; 88 trains; a Bugatti railcar set the 1934 world rail speed record at 196 km/h). Sources: Wikipedia (Bugatti Royale); Bugatti newsroom (Autorail).