Porsche 963 RSP Le Mans Prototype Reimagined for the Road

Porsche has unveiled the 963 RSP, a one-of-a-kind road-legal prototype based on its current LMDh race car, built to commemorate 50 years since the creation of the road-going Porsche 917 made for Count Rossi. The RSP is not a showpiece dressed up like a racer—it is a real-deal, purpose-built LMDh chassis that's been lightly adapted for road use, complete with French license plates.

The 963 RSP finds its inspiration in the 917 that Count Rossi, heir to the Martini & Rossi fortune, once drove on public roads in the 1970s. That car retained its racing underpinnings but was made just roadworthy enough to be enjoyed outside the racetrack. Similarly, the RSP maintains the DNA of Porsche’s LMDh 963, the hybrid prototype currently competing in IMSA and the World Endurance Championship, while incorporating the bare essentials for limited street use.

The project was initiated quietly within Porsche Cars North America (PCNA) under the direction of CEO Timo Resch. It began as a "submarine" operation—an internal code word for highly confidential projects involving very few people. The idea was first discussed in October 2023 at Petit Le Mans, to create a tribute to the Rossi 917 that pushed the boundaries of what's possible under modern constraints.

The 963 RSP is a one-off, built specifically for Roger Searle Penske, the namesake behind the “RSP” designation. Porsche saw Penske—owner of both a racing empire and a racetrack—as the ideal candidate to appreciate and operate such a complex machine. The car will eventually be delivered to him after a global showcase.

Creating a road-homologated version of the 963 was deemed infeasible due to the massive compromises required. Instead, Porsche opted for special exemptions to make the RSP road drivable in limited scenarios. The chassis is entirely new and not a reused racecar tub. Design work was done by Grant Larson and the Porsche Exclusive Manufaktur team in Germany, while assembly occurred in a secluded area within PCNA’s Atlanta headquarters.

Changes for road use include increased ride height, softened suspension dampers, integrated turn signals, license plates, and even a horn. Interior touches like Alcantara trim in the style of the original 917, leather-wrapped steering grips, and a 3D-printed removable cup holder make it a tad more livable, though it still features an FIA racing seat with six-point harnesses.

Under the bodywork lies a 4.6-litre twin-turbo V8 engine derived from the Porsche 918 Spyder—an evolution of the RS Spyder LMP2 car. It shares 80% of its components with the 918’s engine and is paired with an 800V hybrid system featuring a Bosch motor and a Fortescue Zero battery mounted beneath the carbon tub. The transmission is a seven-speed sequential Xtrac unit.

Although Porsche hasn't published exact figures, the race-going 963 typically makes around 700 hp, depending on Balance of Performance (BoP) rules. For the RSP, the powertrain has been recalibrated to run on pump fuel and provide smoother hybrid deployment for low-speed usability.

Aerodynamically, Porsche made minor revisions to make the car more compliant for street use while maintaining the race-ready look. Closed-in vents around the wheel wells, softer damping, and treaded Michelin rain tires on 18-inch OZ wheels help adapt the RSP for road conditions. However, a startup still requires a laptop and a technical crew.

The RSP has been granted temporary road-use approvals, including license plates used for automotive prototype testing in France. Porsche ambassador and racing legend Timo Bernhard recently drove the car on public roads near Le Mans alongside the original Rossi 917, calling the experience “unreal” and noting how friendly and composed the RSP felt in comparison to the race car.

The car will now appear at Le Mans, then travel to the Goodwood Festival of Speed and Monterey Car Week before being delivered to Penske. It will also be displayed briefly at the Porsche Museum.