The Porsche 911 Carrera RS was developed from the standard 911S to compete in the FIA Group 4 category.
This category was more focussed on production-based race cars than track-only prototypes, and as such Porsche needed to build 500 examples of the Carrera RS 2.7 to homologate it for competition.
Porsche 911 Carrera RS 2.7
There was much concern at Porsche as to whether they’d be able to sell 500 of them. The Carrera RS 2.7 is a stripped down performance car with many of the luxuries removed for weight savings, and the worry was that there would be a limited market for a car like this.
Porsche officially unveiled the new model at the 1972 Paris Auto Show and before long the initial production run of 500 cars had all been pre-ordered by customers. By the time the Carrera RS 2.7 was replaced in 1974 Porsche had sold 1,580 of