Yes!
To continue the manufacturer's stronghold in the sub-2 litre GT racing class, Porsche set out to design a completely new car in 1963. This decision was sparked by the introduction of new cars from Abarth and Alfa Romeo, designed specifically for the GT class. Porsche's line up for 1962 consisted of the 356 Carrera 2, which was equipped with a two litre version of Porsche's quad cam four cylinder boxer engine. It was basically a modified road car and the German manufacturer figured more was required to take on the new Italian competition.
For homologation purposes, at least 100 examples of the new car had to be produced in twelve months. This would require a road going version, because Porsche was highly unlikely to sell 100 full blown racers. In order to free resources for the project, the expensive Formula 1 program was dropped. In theory the development costs of the GT racer would be earned back by selling them. The F1 project on the other hand did not offer much in return, except for the potential strengthening of the manufacturer's racing heritage.
Porsche's engineers had to start with a clean sheet, because the spaceframe construction used on previous sports racers like the Type 718 was too expensive and time consuming to built for what was basically a production car. What they did carry over from the 718 was the mid-engined layout, until then reserved solely to the marque's full blown racers. A combination of a steel ladder frame and a glass reinforced plastic (GRP) body was chosen. This was the start of a long line of 'plastic' bodied Porsche racers.
Responsible for the design of the GRP body was Ferry 'Butsi' Porsche, grandson of Ferdinand Porsche. He used some cues and the windscreen of the 718 Coupe and turned it into one of the best looking cars ever constructed. Production of the body was outsourced to airplane manufacturer Heinkel, who were able to produce two bodies per day, which was twice as fast as Porsche could produce the chassis. The body was bonded on the frame, which resulted in a chassis far more rigid than the spaceframe chassis used in the previous racers.
At the start of the project the engineers planned on using Porsche's all new two litre flat 6 engine, which was designed for the upcoming 901/911 model. Unfortunately, the engine's development was hampered and it was not ready yet in time for the 100 example production run. As a stop gap, the four cylinder engine from 356 Carrera 2 was uprated to produce 180 bhp in race trim. It retained the unique shaft driven overhead camshafts. Bolted directly on the 'old' engine was a new five speed gearbox, which was also developed for the new road car.
Three prototypes were constructed and tested heavily in the fall of 1963. After various modifications were carried through, the car was first shown to public late in November. Internally it was known as the '904', but it was marketed to the public as the 'Carrera GTS'. Today it's commonly referred to as the 904. Within two weeks all but 21 of the 90 examples available for the public were spoken for. Production started soon after in a completely new factory, constructed to produce the new 901/911 model. By April of 1964 enough examples were constructed to homologate the 904 as a GT.
Although it took until April for the cars to be homologated, the cars were already entered in various races. At Sebring the Lake Underwood and Briggs Cunningham driven 904 finished 9th overall and 1st in the prototype class. This was the start of a highly successful racing career, with overall victory in the Targa Florio and many class victories in races like the 24 Hours of Le Mans. Underlining the car's versatility was a second place finish in the snow covered 1965 Rallye Monte Carlo.
Throughout 1964 Porsche continued to develop the 904 and provided their customers with various new parts to keep the cars on the pace. Two of the works cars were fitted with a two litre version of the Formula 1 racers eight cylinder engine and later in the year the six cylinder engine finally made its introduction. These versions were not built in sufficient quantities to be homologated, so they raced in the prototype class only. Larger ducts for cooling the bigger rear brakes is an exterior feature of the 904/6. It was eventually replaced in 1966 by the 906 prototype racer.
Today the 904 or Carrera GTS remains as one of the finest and most successful Porsches ever constructed. It kickstarted a program of racing cars, that would eventually result in the all conquering 917. It also holds a unique spot in the manufacturer's history as the only real dual-purpose sportscar Porsche ever built.
