This Porsche 911 is powered by a real, genuine Formula 1 engine that once sat in a race-winning McLaren.

The video shows its public debut at the Goodwood Festival of Speed.

Back in the mid-Eighties, McLaren used 1.5-litre, twin-turbo V6 TAG engines. TAG was simply the investment group that funded the project – the engines were actually the work of Porsche.

Over the course of three seasons from 1985, the TAG engines powered Alain Prost to the ’85 and ’86 Driver’s Championship crown, and secured the ’85 Manufacturer’s title. A total of 25 wins were scored from 64 races.

Whilst developing the engine, Porsche ran one in a 911 mule. It looked like any other 911 – apart from a set of Ruf wheels – but the engine was in full race spec, producing around 750hp.

It is that mule that inspired the build of this car. It has been put together by Lanzante, the British outfit best known for developing early racing versions of the iconic McLaren F1, and converting the McLaren P1 GTR track car to road spec.

Somehow, Lanzante was able to acquire no less than 11 TAG engines from McLaren. It plans to fit each one into a custom-built 911. And these aren’t just spare engines that have been sat on a shelf for 35 years – they have actual F1 racing history. And each car will come with a plaque detailing that history.

The engine is detuned for longevity and driveability, giving 503hp and 310lb/ft of torque. But it still revs to 9,000rpm. And sounds glorious.

Power goes to the rear wheels via a six-speed Porsche gearbox with custom ratios and limited-slip diff. Top speed is a claimed 200mph.

The chassis is updated with coilover suspension all-round. A carbonfibre bonnet, engine cover and aluminium doors reduce weight down to around 1,100kg.

The price for all this? £1,095,000. Ouch.

It’s worth noting, though, that it’s possible to spend that much money with Singer very easily. The historical connection arguably makes the 911 TAG even more desirable so we have no doubt that Lanzante has long since sold all 11 of them.

By Graham King