In 1953 Porsche created a series of 550 prototypes and 550-03 became the most important car in Porsche history by winning the 1954 Carrera Panamerica with Hans Herrmann at the wheel. This singular victory lent the Carrera nameplate to future models and also marked the first international victory of a mid-engine car. Only 15 prototypes were made until regular production began in 1954 of the Porsche RS Spyder.
The 550A was based on Porsche’s first purpose-built racing car, the mid-engined RS 550 Spyder. Appearing at the end of 1956, the 550A differed from its predecessor by use of a full tube spaceframe with several rear supportive cross-members, rather than the heavier welded-up sheet steel internal structure of the 550. The rear swing axles of the 550 were replaced by a new low-pivot arrangement that made handling much more predictable.
The Porsche 550 Spyder was introduced at the 1953 Paris Auto Show. It was simple, small and packed a real punch. It was Porsche's first production racing car. The car was completely street legal, so it could be driven to the races and back home. A really special engine was developed for it, engineered by Ernst Fuhrmann. It was a flat DOHC engine, meaning it had 4 overhead camshafts like the Porsche type 360 design for Formula 1.
One year before Porsche started production of the legendary RS Spyder, they experimented several unique 550 Prototypes. Two of these were fitted with removable hardtops that transformed the diminutive roadster into a sleek coupe. These were quite successful on faster circuits, but the roadster was later preferred as a more saleable car. The Coupes were retained by the factory to contest the Carrera Panamericana race.