The Porsche 917 is a racecar that gave Porsche its first overall wins at the 24 Hours of Le Mans in 1970 and 1971. Powered by the Type 912 flat-12 engine of 4.5, 4.9, or 5 litres, the 917/30 variant was capable of a 0-62 mph (100 km/h) time of 2.3 seconds, 0–124 mph (200 km/h) in 5.3 seconds, and a top speed of over 240 mph (390 km/h).
There are at least nine variants of the 917. The original version had a medium-long tail with flippers, but had considerable handling problems at high speed because of poor bodywork aerodynamics. The Weyer-Gulf team then experimented with a shorter tail, and solved the aerodynamic and handling problems at testing sessions at the Österreichring, at the expense of some top speed. Porsche adopted these changes into the 917K, which dominated in the 1970 and 1971 World Sportscar Championships.
In 1971, a variant of the 917K appeared with an altered tail and shark fins, which together reduced drag and maintained down force. These versions produced around 620 bhp. There were also streamlined versions for Le Mans (1970 917L and 1971 917LH) that were 20 mph faster in a straight line. In 1971 Jo Siffert raced an open-top 917PA Spyder (normally aspirated) in the 1971 CanAm series. There is also the "Pink Pig" aerodynamic research version (917/20), and the turbocharged 917/10 and 917/30 CanAm Spyders. Porsche 917s also raced in the European Interseries in various configurations. In the 1973 Can-Am series, the turbocharged version Porsche 917/30 developed 1,100 bhp (820 kW).
Source: Wikipedia (original)