The UK is known for plenty of things, but it’s not all fish and chips and dodgy Russian oligarch money. It’s also surprisingly permissive when it comes to registering vehicles for public roads. Thanks to a process called “Individual Vehicle Approval,” it’s possible to road-register cars that would likely be met with exasperated spluttering if you were to try the same thing in Germany, Japan, or most states in the US.
Take, for example, the Icon 917K, a street-legal replica of one of Porsche’s most famous racing cars. Yes, the UK will let you register a road-going replica of the car that dominated Le Mans (and the rest of sports car racing) from 1970 until the oil crisis kicked in. British journalist (and friend of Ars) Jonny Smith has driven it for the Late Brake Show:
The original Porsche 917 is one of the most famous examples of creative rule interpretation in racing. The organizers at Le Mans changed the rules for 1969, such that prototypes—purpose-built creations just for racing—were limited to engines of just 3 L of capacity. Larger, more powerful engines were still allowed as long as the manufacturer built at least 25 cars.
Porsche’s Ferdinand Piëch, who was running the motorsport department at the time, saw this loophole and convinced his bosses to approve such a program. Made from a lightweight space frame with fiberglass body panels, the 917 was powered by a 4.5 L flat-12 engine that generated 520 hp (388 kW).
The car was not initially a success. The concept of downforce was basically unknown beyond some experiments being conducted by Chaparral’s Jim Hall; instead, engineers and designers were almost entirely focused on cutting drag—particularly at Le Mans, due to its 3-mile (4.8-km) Mulsanne straight. Far from generating downforce, the original 917’s body did the opposite, inducing lift as speed rose.
More than one driver is alleged to have broken the car “accidentally on purpose” in the name of self-preservation, an understandable move given the fragility of the space frame and the fact that the driver’s feet were ahead of the front axle.
In 1970, John Horsman, chief engineer with John Wyer’s team, noticed a lack of dead flies and gnats over the rear bodywork, providing visual evidence that the airflow was detaching from the car. The team cut up some aluminum sheeting to develop new bodywork to solve the problem, thus creating the 917K—”K” for kurzheck, or “short tail.”
Wyer’s Gulf Oil-liveried 917Ks are the most famous, thanks to race wins and a starring role in Steve McQueen’s Le Mans, but they did not win the 24-hour race in France. That honor went to a 917K run by Porsche Salzburg. A 917K won the following year as well, despite Porsche developing the car into the 917/20, affectionally known as “the pink pig.”