The Porsche 718 is an open-cockpit racing car built by Porsche between 1957 and 1962.
The 718 was a development of the successful Porsche 550A with improvements being made to the body work and suspension. The new front frame resembled the letter K if viewed from the front and this led to the car being referred to as the RSK. 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 car made its racing debut at the 1957 24 Hours of Le Mans driven by Umberto Maglioli and Edgar Barth. The car failed to finish the race due to an accident.
For the 1960 season the FIA made changes to the regulation regarding the windscreen and cockpit size. These rules changes together with a larger (1.6 litre) Type 547/3 engine, developing 160 horsepower (120 kW) and a new double wishbone rear suspension brought about the RS 60 model. The RS 60 brought Porsche victory at the 1960 12 Hours of Sebring with a car driven by Hans Herrmann and Olivier Gendebien. 1960 also saw Porsche win the Targa Florio with Hans Herrmann being joined on the winner podium by Jo Bonnier and Graham Hill. The RS 60 also ensured that Porsche successfully defended their European Hill Climb Championship for the third year in a row.
A two-litre version, the W-RS was developed in 1961. Initially fitted with a 4-cylinder engine, the car was later fitted with an enlarged flat-8 air-cooled engine from the Porsche 804 Formula One car which was developed to produce 240 horsepower (180 kW). A W-RS finished 8th at Le Mans in 1963. The W-RS continued Porsche's success in the European Hill Climb Championship with Edgar Barth claiming the title in 1963. Porsche would go on to win a European Hill Climb Championship every year until 1982, a total of 42 titles.
The W-RS continued racing until 1964 when it was replaced by the 904.
A Coupé version was developed from the RS 61. Initially fitted with a 4-cylinder engine, this car was also upgraded to an 8-cylinder F1 derived engine which produced 210 horsepower (160 kW). The car was also fitted with disc brakes. A GTR Coupé driven Jo Bonnier and Carlo Maria Abate won the 1963 Targa Florio making it three wins at the event for a 718 car.
A new Formula Two for 1.5 litre engine cars was introduced in 1957. Due the central location of the steering box, the 718 was easily converted to single seater specification and Porsche made their F2 debut with victories at Reims and AVUS in 1958. In 1959 other RSK's were converted for single seater racing and at the XV B.A.R.C. '200' at Aintree in 1960 Porsche scored a 1–2–3 victory with Stirling Moss, Jo Bonnier and Graham Hill all in 718's. The feat was repeated again later in the year at the race at Zeltweg, Austria.