Oh yes, Porsche has built a one-off, 671bhp road-legal* V8 963 hypercar

Porsche has shocked the motoring world by unveiling a brand-new road-going performance car. While it shares many things with road-going performance cars – headlights, turn indicators, a horn – it is unlike almost anything you can currently purchase.

Because this one’s spun directly off a car that’s won multiple endurance racing world titles. Welcome, one and all, to the mad, bad, and entirely brilliant Porsche 963 RSP.

It’s a version of Porsche’s WEC and IMSA competitor built to mark 50 years since a certain Count Rossi drove the all-conquering Porsche 917 from Zuffenhausen to Paris. Like that car, this one’s been tweaked so it’s street legal. Sorta.

“How could we reimagine [the 917’s] story in today’s time?” asked Porsche’s North American boss Timo Resch. The answer, as you can see, is quite clear.

“The 917 from the story was every inch a race car – albeit one driven on the road – and we took the same approach with the 963 RSP,” added Resch. “It uses beautiful materials of the best quality available, but is still every bit a race car underneath.”

A fine place to start. For this very special project, the small team in charge of the RSP - including Porsche's Sonderwunsch department - decided early on that they’d need a brand-new 963 chassis, not an existing one. To which a number of very subtle, very important and likely mind-blowingly complicated changes were made.

The 963’s ride height was raised from a hair’s width to something more suitable for general roads, while the adjustable Multimatic DSSV dampers – designed for sports prototypes, don’t forget – were gaffer taped into their softest setting.

Then came one of the hardest bits: allowing the 4.6-litre, twin-turbo V8 hybrid powerplant to run on regular unleaded. Not race fuel, but the stuff you can get out of a forecourt pump. “Not a small undertaking,” explained Porsche Penske Motorsport MD Jonathan Diuguid.

Amazingly, it’s in race trim, which means the 918 Spyder-derived V8, e-motor and battery combo punches out an incredible 671bhp, only here it’s been treated to an ECU remap to smooth out the power delivery. Top Gear has not long forgotten what the nat-asp 918 Spyder’s V8 sounds like, nor the 963’s race-bred unit. This Will Be Loud.

Not when running on e-power alone, which the 963 RSP is capable of for short stretches. Though Porsche has ensured its lucky new owner will want to do rather longer stretches because the interior is, of course, the biggest departure from the race car.

You could live in here. Soft tan leather adorns the entirely bespoke cabin, with a single piece carbon driver’s seat clad with additional cushioning and a fixed headrest. Air-conditioned, too. There’s Alcantara in the roof lining and pillars, leather for the steering wheel, and – in a “light-hearted” touch – a detachable 3D-printed cupholder capable of holding… a Porsche mug.

A special panel sits next to the driver to store a helmet and the steering wheel, while dig around and you’ll spot “obvious references to the 917”. One of these is deeply nerdy and deeply cool: the bespoke end plates for the ventilation system have been shaped to mimic the fan on top of the 917’s flat-12 engine. Yes, Porsche. More of this please.

Indeed, the biggest tribute to the 917 comes in the exterior colourway. It’s a paint-to-sample colour verified by Porsche records as being the same ‘Martini Silver’ as Count Rossi’s 917. And unlike the other 963s that feature custom wraps, this one’s been painted, and finished with a triple-layer lacquer.

Naturally some bodywork changes were required. The head- and tail-lights the most obvious, new air vents, closed-off blanking plates on the rear wing, an enamel Porsche badge on the nose, proper wet road tyres wrapped around 18in OZ racing wheels, and of course, mounting points for the license plate. There are indicators, too. And a horn.

Perfect for its new owner, then. A certain… Roger Penske. Hence the ‘RSP’ moniker. “I thought it was appropriate to get Roger Penske himself involved in this project and ask for his support,” said Resche. “I wasn’t quite sure if he was going to say ‘don’t get me distracted me from my race efforts’, or if he would say ‘oh that’s a good idea’.

“He said ‘that’s a very, very cool idea’. He liked it from the very beginning. He said if a car should be done it should be true to the 963. That the race car character shouldn’t be changed. From this early stage, we came to the conclusion that he would be the perfect customer for such a car,” he added.

The only customer. It was never intended to be a fully homologated road legal 963 – indeed it needs special dispensation to run in France at the Le Mans 24hr weekend, and Porsche has got an exemption from the EPA in the States because “they understand it’s a one-of-one” and “how special it is”. But that’s it – it’s not a fully road-registered car.

And Porsche isn’t about to start churning these out like they do Cayennes. “It’s very different to 1975,” a Porsche spokesperson told Top Gear. “It’s far more difficult to [homologate] now. It’s a huge, huge task, and would very much change the character of the 963.

“Roger was very keen to ensure the character of the car – that rawness – was retained as much as possible.” So it’s a one-off.

Though, Porsche’s director of LMDh factory racing Urs Kuratle, told TG: “Of course we will not build exactly the same one again because that’s the nature of the project. But… never say never. As Porsche, we like to sell cars first of all, and if there is an opportunity, a possibility to do it again at a later stage, why not.”

Resche added: “I think this is part of the Porsche DNA, it has always been a start point for things to evolve based on what we hear from the public, from the enthusiasts. So I would keep it open.”

And is there any desire for this Penske 963 to basically blitz every single road car lap record around the world? “That’s a question for its owner!” Porsche told TG. “Competition is at the heart of the brand, and we’re a curious group. It’s not part of the agenda for the car, but who knows.

“Never say never.”