The 1956-1959 Porsche 550A

Overview

The 718 RSK established the evolutionary successor to the 550A through enhanced engine displacement and refined aerodynamic characteristics. Produced from 1957 through 1962, this mid-engine racing car employed a 1.5-1.6-liter four-cam flat-four engine producing 142-160 horsepower depending on tune specifications. The RSK designation referenced the German Rennwagen, Spyder, Kompressor (Racing Car, Spyder, Compressor) classification. The vehicle established Porsche's racing dominance throughout the late 1950s and early 1960s.

The 718 RSK represented evolutionary refinement of the 550A platform, incorporating improved engine technology and aerodynamic enhancements. The limited production run of approximately 34 examples established notable rarity and collectibility. The racing success included multiple international victories, validating the design against contemporary competitors.

Engineering & Development

The 718 RSK employed a 1.5-1.6-liter naturally aspirated four-cam flat-four engine mounted aft of the driver, producing between 142 and 160 horsepower depending on engine variant and fuel specification. The spaceframe chassis construction maintained light overall mass enabling superior power-to-weight ratios. The transmission incorporated a four-speed manual unit with direct mechanical linkage.

The suspension employed double-wishbone front and independent rear configuration with refined spring rates and damper calibration. The aerodynamic design incorporated subtle refinements including a more integrated body with enhanced form coherence compared to earlier variants. The braking system employed ventilated aluminum-alloy drums with mechanical actuation.

The engine variants supported both normally aspirated and supercharged operation, with compression ratios and fuel injection calibration varying between competition classes. The power delivery characteristics proved suitable for international racing success across multiple vehicle classes.

Market Variants

The 718 RSK appeared as both works racing vehicles and customer competition platforms, enabling private teams to pursue international racing programs with Porsche technology. Limited production established exclusivity and rarity. American buyers required private importation, as Porsche did not officially export to North American markets.

The interior minimized equipment, incorporating simple bucket seats and essential instrumentation. The open cockpit design emphasized driver engagement and mechanical transparency.

Significance

The 718 RSK demonstrates Porsche's commitment to evolutionary refinement of proven platform architecture, establishing continuous improvement patterns that characterize the company's design philosophy. The 718 designation later appeared on Porsche's turbocharged road car lineup, referencing the vintage racing heritage. The RSK's racing success across multiple international venues validated the design against established competitors.

The 718 RSK proved that evolutionary engine development focusing on increased displacement and breathing efficiency improvements delivers competitive performance within racing classifications.