Porsche 904

After having withdrawn from Formula One at the end of the 1962 season, Porsche focused again on sportscar racing. The 904 debuted late in 1963, for the 1964 racing season, as a successor to the 718, which had been introduced in 1957. Porsche designed the GTS variant to compete in the FIA-GT class at various international racing events.

The street-legal version debuted in 1964 in order to comply with group 3 appendix J homologation regulations requiring a certain number of road-going variants be sold by the factory. Porsche produced one-hundred and six 904s at four or five a day with a list price of US$7245 (FOB Stuttgart). Orders far exceeded the one hundred car requirement to satisfy homologation rules and more cars could have been sold. The 904 marked the beginning of a series of sportscars that culminated in the dominant 917.

Making an inauspicious debut at Sebring in 1964, where it suffered clutch trouble, a four-cylinder 904 took an astounding first overall at the Targa Florio. It went on to a third at the Nürburgring and a perfect finish at Le Mans. Both times, all five starters finished, placed in the top twelve overall, among many much more powerful cars. 904s showed remarkable durability; theyalmost always finished, and at Reims in 1964, a customer car fresh from Stuttgart, driven to the track, went on to win without the need for any spares at all.

For 1964, 904s racked up a 1-2 at the Targa Florio and class wins at Spa, Sebring (co-driven by Briggs Cunningham and Lake Underwood), the Nürburgring, Le Mans, Watkins Glen, Zandvoort, Canada, and the Paris 1000 Kilometer, in the process taking SCCA's C-Production and E-Sports Racing titles. In addition, it won rally events including the Tulip, Munich-Vienna-Budapest, Geneva, and highly acclaimed Alpine Rally.

For 1965, results were equally impressive, seeing wins at the Spanish, Rossfeld, Hellbronner, and Gaisburg rallies, as well as a class win and second overall in the Monte Carlo Rally which saw just 22 finishers in the points, out of 237 starters. In addition, 904s won their class at the Monza 1000 Kilometer, Targa, Spa, Daytona Continental, Le Mans, and Zandvoort, among others, repeating their E-Sports title win and adding an SCCA E-Production championship.