The fiberglass-to-metal body and chassis bonding worked fine for the
projected race life of a 904, then rust began to separate the two elements
projected race life of a 904, then rust began to separate the two elements
With the proven 356 Carrera Abarth having served formidably for three seasons, the imminent arrival of the two-liter Simca Abarth meant that Porsche was going to have to raise the stakes for 1964.
Early in 1963 Ferry Porsche’s son, “Butzi,” finished a full size model of the new design. Although used already on the body panels of their Grand Prix car, this was the first time Porsche planned to use fiberglass on a sports car. In typical Porsche fashion, this new material was put to additional use on the 904 and it increased torsional rigidity by bonding the fiberglass to the steel ladder-frame chassis.
Not only was the fiberglass body to benefit structurally and in weight savings, but it was cost-effective as well. Rather than undertaking this aspect in-house, the fiberglass bodies were subcontracted to Henkel, an aircraft parts supplier.
The new design was a low-slung, slippery two-seater, and using all of their experience, Porsche created formidable technical specifications to ensure the new race car would possess exceptional handling characteristics. Thanks to the front-mounted fuel tank and mid-engine placement, weight balance was 48/52 when full, changing to 42/58 when empty.
The 904 evolved with the new six-cylinder engine and competition application was inevitable. However, it was clear that this all-new engine would not be ready in time for the 1964 season, so Hans Meyer (from the Grand Prix project team) was employed to entice more power from the existing four-cylinder, four-cam Carrera engine used to good success powering the 356 GTL (the L stood for lightness, about the only thing missing from the standard 356 upon which the chassis was based).
Designated Type 587/3, the final evolution of the 2-liter Carrera engine produced a very healthy 180 hp at an ear-splitting 7,200 rpm. The engine was mated to an all-new five-speed transaxle, known as the type 901 (and later used in the first years of the 911), and with a dog-leg first gear, it dispensed power through a ZF limited slip differential integral with the gearbox.
Inside the svelte 904, the seats were located in a fixed position, and Porsche designers gave the driver the opportunity to adjust the pedals to three separate locations. The steering column was telescopic.
In order to homologate the car, Porsche had to build one hundred examples. The company needed to fill order books quickly to meet the March 31 cut-off date, allowing the car to tackle the premier sports car races in the 1964 season. Henkel produced the bodies, which were painted, wired, and plumbed for fuel and oil tanks at a rate of two per day with deliveries starting in November 1963.
Meanwhile in Zuffenhausen, using the brand new factory-built for the production of the Type 901 Coupe (later forced to be named the 911), Porsche built one 904 per day.
As expected, the 904 GTS proved to be an outstanding race car and in 1964 alone a 904 came in first over-all in the Targa Florio, humbling machinery with far greater displacement. The 904 also recorded class wins at Le Mans, Sebring, Nürburgring, Spa, Reims, and many other courses in both factory teams and private hands. (Courtesy of Christie’s)