Developed for endurance sports car racing, the 906 was a street-legal racing car that raced in the FIA's Group 4 class against cars like the Ferrari Dino 206 P. They often won their class behind the much larger prototypes such as the Ford GT40 Mk II and Ferrari 330 P3/4. Based off the same principles as the 904, the 906 used a boxed steel chassis with a fiberglass body that added rigidity to the design. The greatest success of the Porsche Carrera 6 "Standard" was undoubtedly the victory at the Targa Florio 1966.
The technology in racing during the mid 60s was shifting from carburetors to fuel injection. Porsche began experimenting and the Bosch injection system proved to be the most reliable. Though the performance did not increase, it did provide superior throttle response over the Weber carburetors, and it was easier to tune. To compliment the new engine, a new body was created which reduced drag levels. Porsche dubbed the resulting car, with its new engine and body work, the 906E, with the 'E' representing 'Einspritzung, or injection.
The 906 LH was capable of achieving 174 mph/280 km/h with its 2-litre engine (906 K: 165 mph/265 km/h). At high speed the long tail started to create lift (opposite to downforce), which made the car go fast on the straight, but was dangerous to drive. At Le Mans, the 906 LHs with their experimental bodies competed in the 2-litre prototype class.
A spider body was fitted, and its inaugural appearance was at the Swiss Ollon-Villars hillclimb where it was met with disappointing results that were clearly to-do with poor testing and rushed development. The Ferrari's easily dominated the event and sent Porsche and their ''Ollon Villars Spyder' back to the drawing-board.
Four factory 906s received an air-cooled eight-cylinder boxer engine of the type 771, which was already used in the 904/8. The engine had a displacement of 2.2 liters with a compression of 10.2: 1 and vertical shafts that drove the two overhead camshafts per cylinder bank. The maximum output was 198 kW (270 hp) at 8600 rpm. All vehicles were equipped with a five-speed manual transmission of the type 906 and a ZF limited-slip differential . The gear ratios could be exchanged as required without removing the gear.