The Porsche 904 is an automobile which was produced by Porsche in Germany in 1963 and 1965. It was officially called Porsche Carrera GTS due to the same naming rights problem that required renaming the Porsche 901 to Porsche 911. After having withdrawn from Formula One at the end of the 1962 season, Porsche focused again on sports-car racing.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. Several versions were made, including one with a flat six engine and a flat eight engine.