Due to the Gulf Oil Crisis of the 1970s and more strict emission laws, Porsche like many other car manufacturers at that time, reduced the power output of its naturally aspirated flat-six engine to 180 PS (132 kW; 178 hp) thus creating a huge power and performance gap in its naturally aspirated 911 lineage and the Turbo.

Seeing the potential of the naturally aspirated engine to generate a higher power output while maintaining fuel economy, Ruf introduced the SCR in 1978 based on the 911 SC.

Key changes over the 911 SC included an engine with an enlarged capacity of 3,185 cc generating a maximum power output of 215 PS (158 kW; 212 hp) at 6,000 rpm.

[2] Other aesthetic changes included the "whale tail" spoiler found on the 930 Turbo, a deep chin spoiler at the front, a new front bumper with integrated round brake cooling ducts, optional wide wheel arches as found on the 930 Turbo and special Ruf 5-spoke alloy wheels.

The new SCR has carbon fibre body work, an integrated roll-cage and a 4.0-litre naturally-aspirated flat-6 engine based on the unit found in the Porsche 911 GT3 RS 4.0, generating a maximum power output of 510 PS (375 kW; 503 hp) and 470 N⋅m (347 lb⋅ft) of torque with a red-line of 8,200 rpm.

The car has a 6-speed manual transmission directing power to the rear wheels and an in-house developed push-rod suspension system.