The Porsche 718 RSK is a series of one- or two-seat sports-racing cars built by Porsche from 1957 to 1962. An open-wheel single-seat model was developed for Formula racing. The 718 was a development of the successful Porsche 550A with improvements made to the body work and suspension. The car's full name is 718 RSK, where "RS" stands for RennSport (sports-racing) and the "K" reflects the shape of the car's revised torsion-bar suspension. It had a mid-engined layout and used the 142 horsepower (106 kW) 1.5-litre Type 547/3 quad-cam engine introduced in the 550A. The 718 RSK served as inspiration for the 2017 Porsche 718 Cayman and Boxster models.