Throughout the 1973 season, Porsche participated in several races, fielding modified versions based on the Carrera RSR. The 2.8-liter engine (300 horsepower) was tuned for racing, then the displacement was stretched and power eventually increased to at least 330 bhp. The car served as a laboratory in view of subsequent developments, in particular the entry into force of the new group 5 regulation starting from 1976. There were many aerodynamic configurations adopted on the 1973 Carrera RSR, which being registered in the prototype category allowed for a maximum of experimentation . Over the course of the season the car proved to be very competitive, even winning the Targa Florio.