The Porsche 906 was announced in January 1966, designed for the 1966 World Sportscar Championship. It was intended as a Group 4 Sports Car, requiring a minimum of 50 cars to be produced for homologation, with 65 ultimately built. Ferdinand Piëch, grandson of Ferdinand Porsche, led the development of the 906, aiming for maximum lightweight construction.
The 906 was designed as a successor to the Porsche 904 Carrera GTS. Piëch’s goal was to reduce weight by replacing the 904’s steel body with unstressed fiberglass. This construction method allowed for structural support and a smoother finish, resulting in a finished product weighing around 580 kg (1,280 lbs), approximately 250 lbs lighter than its predecessor. The car was typically fitted with a 901/20 6-cylinder engine producing 210 horsepower at 8,000 rpm, though an 8-cylinder engine was sometimes substituted for hillclimbing events.
The 906 debuted at the 1966 24 Hours of Daytona on February 6th, finishing 6th overall and winning its class against Ferrari Dino 206 Ps. At the 12 Hours of Sebring in March, five 906s competed, with Hans Herrmann and Herbert Müller finishing fourth overall and winning the class, followed closely by two other 906 entries. In April, at the Monza circuit, a 906 finished 4th overall, beating several Ford GT40s and Ferrari 330P3s.
The 1966 Targa Florio saw a privateer 906, driven by Willy Mairesse and Herbert Müller of Scuderia Filipinetti, win overall after the factory cars collided. At the 1000km Spa race, a Racing Team Holland entry finished 15th overall, securing a class win. The 1966 1000km Nürburgring saw 906s finish 7th, 8th, 10th, and 11th overall.
The 1966 24 Hours of Le Mans saw Porsche achieve a 4-5-6-7 sweep in the S 2.0 class with the 906, finishing behind the dominant Ford GT40 Mk.IIs. The car’s success contributed to Porsche winning both World Championships in their classes. Later in 1966, development of the 906 led to the creation of the Porsche 910, with new chassis being designated as such.
The 906 also saw success in North America, with Ken Miles winning the 2.0-liter class at the Las Vegas Stardust and Laguna Seca USRRC races in 1966. These victories continued through 1967 and 1968, with Peter Gregg also securing wins at the Bahama Speed Weeks. Comedian Dick Smothers and Fred Baker also drove a 906, winning their class at the 1969 Bahama Speed Weeks.
The 906 featured a wind-tunnel-tested body, achieving a top speed of 280 km/h (170 mph) at Le Mans. It incorporated gull-wing doors and a mid-ship mounted engine covered by a plexiglas cover. The car utilized a modified 901 engine, similar to that found in the Porsche 911R, with exotic metals like titanium in the connecting rods and magnesium in the crankcase to enhance performance. It also reused suspension components from the Porsche 904 and a 5-speed manual gearbox from the Porsche 911, but retained the 5-nut wheel mounting system of a road car.