Rank 17 documents the Porsche 917 Langheck — the long-tail evolution that gave Porsche its second consecutive Le Mans overall victory in 1971 and sealed the 917 as the most feared sports-prototype of its generation. Chassis 917-021 wore John Wyer's Gulf livery: powder blue with orange bands, number 20, and a rear deck stretched for Mulsanne Straight stability. The flat-12 delivered 600 PS from 4.5 litres through a five-speed transaxle in a package weighing just 800 kilograms — numbers that read like fiction until you study the wireframe diagrams beneath the side profile. Marthe and Helmut Marko drove the Langheck to a distance record that stood for decades, turning the 917 from a terrifying 1969 debut into a mature endurance weapon. Wallimilist renders the Gulf side profile, number 20 roundel, technical three-view wireframes, and specification table exactly as the master PNG dictates — stamp perforation border, 917 LE MANS kicker, and curator copy on Wyer-era Gulf dominance.