1907 Fiat F-2

Gianni Marin, The Motor Car, London House and Maxwell 1963

The FIAT F-2  was built for the French Grand Prix, which did not restrict engine displacement, rather they chose fuel consumption as a limit. Cars had to deliver at least 9.4 miles per gallon. 
Fiat chose a 4 cylinder 16,277 cc (627 cu in) engine producing 110 hp at a mere 1000 rpm. The car won the race, averaging 70.5 mph.