The 4.0-litre engine of the current RS runs a 102x81.5mm bore and stroke, making it the largest six-cylinder boxer to make production. But insiders are now claiming the engine in a more potent RS would be 4.2 litres in capacity, pushing the engine’s stroke up to 85.1mm.
RUF has already demonstrated the flat six's potential for a larger capacity with its 964 911-based SCR 4.2, which was first demonstrated at this year’s Geneva motor show. That car features a water-cooled 4.2-litre flat six that produces 518bhp at 8370rpm and 369lb ft of torque at 5820rpm.
This is substantially more than the 4.0-litre engine of the current RS, which offers 493bhp at 8250rpm and 339lb ft of torque at 6250rpm.
Insiders say the RUF unit previews what’s to come from Porsche, and a more potent GT3 RS would seem like the most likely candidate to run such an engine.