When it comes to air-cooled 911 restomods, Singer Vehicle Design typically gets all the headlines. But across the pond, Oxfordshire-based Theon Design has been quietly building some of the most compelling interpretations of the beloved 964-generation 911. Their latest commission for a U.S. customer delivers a power-to-weight ratio that embarrasses Porsche’s current track weapon, the 992 GT3 RS.
Formula 1 Meets Zuffenhausen
Specs-wise, the new commission is lightweight and delivers 421hp driving just 2,540 pounds, which works out to roughly 6lbs per horsepower, edging past the GT3 RS’s 6.2lbs per pony, despite the modern car’s 518-horsepower advantage. Theon pulled it off by stripping a donor 964 down to bare metal and rebuilding it with F1-grade carbon-Kevlar bodywork.
Only the doors remain in steel so as to preserve that satisfying 911 “thunk” we all know and love. Everything else, including the roof, gets the aerospace treatment that’s lighter and stiffer thanks to additional seam welding that transforms torsional rigidity.
Air-Cooled Alchemy
The heart of this beast is a comprehensively rebuilt 4.0-liter flat-six that produces 421hp at 7,400 rpm. Theon relocated the AC compressor and power steering pump from their traditional perch behind the engine to the front trunk, optimizing weight distribution to an impressive 46:54 split, which is honestly remarkable for a rear-engine configuration.
Breathing takes place through bespoke Jenvey throttle bodies and Theon’s own velocity stacks, while a state-of-the-art ignition system ensures every combustion cycle counts. Power routes through a six-speed manual built to 993 RS specification, paired with a Wavetrac Torsen limited-slip differential for maximum traction.
Modern Sophistication
Dynamic duties are handled via a TracTive semi-active suspension with five settings, while Theon’s bespoke carbon-ceramic brake system features Brembo monobloc calipers gripping 355mm rotors front and rear. Those sit behind 18-inch Fuchs wheels wrapped in Michelin Pilot Sport 4 rubber that can handle both road and track scenarios.
Inside, the customer selected Fresca blue and Picasso ivory leather with intricate six-color woven detailing that takes hundreds of hours to complete. Recaro CS seats provide the requisite support, while a cleverly integrated Alpine head unit deploys electrically from the dashboard when needed. The JL Audio sound system features dual subwoofers tucked into the rear seat delete area.
Each of Theon’s commissions involves an 18-month consultation process where customers can evaluate paint samples under different lighting conditions. This particular car wears Azzuro Thetys Metallic with subtle ghost stripes — a finish that required sending color samples across the Atlantic for approval.
Spec Sheet
Donor Car: Porsche 911 (964)
Engine: 4.0L naturally aspirated flat-six
Power: 421hp
Torque: 330lb.ft
Weight: 2,540 lbs
Power-to-weight: 6.0 lbs/hp
Transmission: 6-speed manual (993 RS spec)
Brakes: Carbon-ceramic with Brembo monoblocs
Wheels: 18-inch Fuchs
Construction: F1-grade carbon-Kevlar body
Pricing & Availability
Theon Design commissions start at $590,000 for U.S. specification, excluding the donor car, shipping, and local taxes. Each build takes 18 months to complete and represents a unique collaboration between customer and creator.
Recap
Theon Designs 964 Porsche 911 Lightweight Restomod
British tuner Theon Designs stripped this 964 Porsche 911 down to bare metal and built it back up with F1-grade carbon-Kevlar bodywork to make it lighter than Porsche’s latest 992 GT3 RS track car.
