Porsche started their long 917 race program in 1969 with a series of 25 identical cars that were upgraded throughout their career. The first major modification was a stability upgrade that came in 1970 with the 917 Kurzheck or short tail. Simultaneously a long tail ‘Langheck’ model was made for top speed down the Mulsanne Striaght.

By 1971 Porsche were experimenting with Can-Am versions and this 917 16-Cylinder Prototype was one of their first test mules. Eventually engineers turbocharged the design, leading to their most powerful variant, the 917/30 Spyder.

In 2007 we ran into the most impressive display of 917s to date at Rennsport Reunion III. A similar caliber of cars should be at this year’s Monterey Historic Races to support Porsche as a feature marque. One such car will be 917-21 currently being restored and documented online by Gunnar Racing of Palm Beach, Florida.