Singer Vehicle Design, a brand known for lavish restorations of air-cooled Porsche vehicles. To make one special Singer 911 stand out from the rest, the California based restorer has announced a collaboration with Williams Advanced Engineering for this latest engine. Furthermore, they have even enlisted Porsche Motorsport engine designer Hans Mezger as a mechanical consultant.

Singer, Williams Engineering to build 500 PS flat-six engine

Unlike Singer's existing engine, which by no means is slow, the new Williams-developed flat-six will still have a 4.0-liter capacity and a 500 PS output. This was done by using a standard Mezger-design 3.6-liter flat-six from a 1990 Porsche 911, which was then bored and stroked to 4.0-liters.

Compared to a standard Singer engine, this has a four-valve cylinder heads, titanium con-rods, aluminium throttle bodies and dual oil circuits installed. Furthermore, the engine also benefits from Formula 1-spec parts such as the inconel/titanium exhaust, carbon fiber intake trumpets, a carbon fiber airbox with a resonator chamber, and ram-air intakes built into the vehicle's rear quarter windows.

Singer, Williams Engineering to build 500 PS flat-six engine

Overall, Singer says the engine will rev beyond 9,000 rpm. Mind you that this engine matches the power output of the current 911 GT3, but is still air-cooled and is naturally-aspirated.

The engine will be installed in a restored 911 commissioned for long-term Singer client Scott Blattner. At the moment, Singer has only released renderings of the William-worked engine, but will make its debut alongside the car's reveal in September. As for the price, Singer rarely releases pricing on special commission models, but do expect it to be very expensive.