It would be perfectly reasonable to think that Porsche restomods—as we currently know them—are largely confined to the air-cooled 911 chassis. Factors such as track width, bodywork, wheelbase, and the fact that the chassis remained fundamentally similar from 1964 to 1989 made for easy interchangeability of parts.
The idea of grafting the body of a vintage Carrera RSR or 911 Turbo onto a water-cooled 996- or 997-generation chassis may strike some purists as sacrilege. But the concept isn’t completely far-fetched. It’s just that few people had attempted to take on such a project to the degree that Christian Ruehle did with the Ruehle F97—the “F” representing the F-Series 911 of 1964-1973, and “97” denoting the 997 of 2005-2012.
The Rundown
Ruehle, the owner of Ruehle Sportwagenbau in Schorndorf, Germany—roughly 20 miles east of Stuttgart—has been restoring classics for over two decades. The idea actually came from his younger clients. They wanted different things compared to the older generations.
“Younger customers,” Ruehle said, “who grew up with modern cars, do have a very different approach to classic cars. They usually opt for reliability over rarity, safety over speed, and modern technologies over carburetors. So we took the expertise that we gained over the past 25 years and developed something radically new; we did not just want to juice up an old car like a 964 to look even older, we wanted to build something with the most modern approach doable; something that will still be modern and safe in a few years, not outdated.”
Ruehle and his team started by taking measurements of a 996 and set an ambitious goal: to have a finished car ready to show at Monterey Car Week in August 2025, leaving them with a tight window of roughly 2.5 months.
Questions arose, of course. How does the bodywork of a shorter air-cooled chassis fit onto the longer wheelbase of a 996 or 997? Does the chassis need to be shortened, or do the body panels of the air-cooled chassis need to be lengthened? Understandably, Ruehle chose to keep the secrets secret. When asked what the most difficult part of the project was, he said, “Keeping the proportions as beautiful as you see them now. There was a lot of massaging involved to get them right.”
Ruehle did confirm that the chassis was not shortened, crediting their success to sheer experience. “It’s truly a lot of work. But, as we have been doing full-body restorations for a long time, it’s not as complicated as it may seem. It’s still sheet metal and sweat.”
The car you see here started life as a 997.1-gen 911 Carrera S, though Ruehle notes that production customer cars will utilize the 997.2 platform. The later generation benefits from factory PDK transmissions, direct fuel injection, and updated Porsche Communication Management. However, if a customer requests a 997.1 as the basis for a build, that’s possible as well.
Our subject F97 wears steel reproduction body panels, including fenders, a long hood, and the doors and roof from a 930-gen 911 Turbo. The front and rear bumpers are made in-house at Ruehle. Knowing that it’s based on a 997, you look for clues that might show where its panels had to be elongated or reshaped to fit the 997’s longer wheelbase, but there aren’t any. One indicator of just how tight the tolerances are is the few millimeters of space between the IPD intake plenum and the engine cover’s grille.
The pre-production F97 is powered by the 997.1 Carrera S’s 3.8-liter flat-six. It also features a couple of performance modifications, including the aforementioned intake plenum, an ECU tune, and a custom Ruehle-built in-house exhaust system. Those upgrades were good for a claimed extra 30 hp on top of the stock 355 hp. Ruehle says engine upgrades depend heavily on local emissions regulations of the car’s final destination.
The build process also helps reduce curb weight. According to Ruehle, “depending on the options you go with, usually about 300 pounds, at least.”
On the Road
Settling into the F97, the first thing that catches your eye is the dashboard. It was designed and made in-house because the original dash no longer fit after the retrofitting of air-cooled-era A-pillars. Ruehle also wanted to bring in more F- and G-Series 911 design elements, like the classic five-gauge layout and the lower trim panel, wearing a red tartan pattern in this pre-production example. They did, however, retain the 997’s Sport Chrono Package chronometer.
Aside from the aesthetics, the mechanical touchpoints are equally good—chiefly, the feel of the six-speed manual paired with a Numeric Racing short-throw shifter. There’s a satisfying weight to it, the throws are shorter, and the engagement is positive. It’s the kind of tactile action that makes you invent excuses to shift.
The car rides on a set of KW V3 coilovers that are built to Ruehle’s own specifications. The setup and the finer settings were carried out by the former Porsche Motorsport engineers who now work at Ruehle. The car rolls on custom-made 17 × 9-inch front and 17 × 11-inch rear Braid Fuchs-style alloys wrapped in 245/40-17 and 275/35-17 Nankang CR-S tires, respectively.
The ride is firm but never harsh, with enough compliance to absorb bumps without drama. In the corners, there’s a touch of body lean, just to let you know it’s taking a set. Turn-in is quick, much like the pointy response of an air-cooled chassis. It’ll understeer when the tires are pushed too hard, but that limit is lofty and foolish to approach on a public road. So a slow-in-fast-out cornering style turns out to be more rewarding.
Ruehle’s exhaust system sets the tone when you start the engine, but not in an intrusive or overwhelming way. The notes have a gritty edge that reaches the ears and travels down the spine. You grow familiar with its vocal range and quickly learn to shift by sound while exploring the rev range of the 3.8-liter powerplant. The engine offers a healthy wallop of low-end torque, instantaneous throttle response, and linear power delivery all the way to redline.
The Verdict
The Ruehle F97 is the kind of car that can re-ignite a passion for driving. It gets under your skin in the best way. Just one screaming-to-redline shift or a precisely carved corner only makes you hungrier for the next one. It’s easy to imagine an F97 owner turning a morning drive into a day-long immersion into sound, G-forces, and a test of skills.
While it doesn’t quite get the coveted “analog” stamp of an air-cooled 911, the feel and the feedback come tantalizingly close. If one had to choose between an air-cooled restomod and an F97 for a spirited drive, it would be a coin toss.
