Twin-Plug 2.9L-Powered 1975 Porsche 911S Coupe G50

This 1975 Porsche 911S coupe was modified in a 911ST-inspired build following the previous owner’s purchase in 2015, with work including seam-welding the chassis and the installation of steel fender flares, a fiberglass hood and decklid, and chassis reinforcements. Power is supplied by a twin-plug 2.9-liter flat-six with mechanical fuel injection with individual throttle bodies and mated to a G50 five-speed manual transaxle with a limited-slip differential. The car has been repainted in light green, and it rides on 17″ Fuchs-style wheels along with Bilstein shocks, Eibach springs, Tarett Engineering sway bars, and 930-specification brakes. Inside, the stripped cabin houses sport seats trimmed in black leatherette and fabric, multi-point harnesses, a roll bar, an aftermarket shifter, and a MOMO steering wheel. The car was sold on BaT in October 2025, and subsequent work consisted of finishing the wheel accents in green and installing green graphics. This modified 911 is now offered on consignment by the selling dealer, a BaT Local Partner, with a clean California title.

The car was stripped and fitted with steel ST-style fender flares, a drilled fiberglass hood and decklid, and fiberglass bumpers before being painted in light green by Kudensport of Santa Paula, California. The chassis received seam welding and reinforcements at that time, rust repair was performed, and a custom ducklid grille, and vented polycarbonate rear quarter windows were added. Additional equipment includes Talbot side mirrors, hood and decklid rubber latches, a Porsche crest hood decal, H4 headlights, and Euro-style taillights. Previously installed vinyl orange over-the-top stripes and lower body graphics were replaced with green counterparts following the 2025 auction.

The 17″ Fikse wheels feature green-finished insets and are mounted with Staggered-width Michelin Pilot Sport tires. Stopping power is provided by 930-specification rotors and orange-finished calipers at each corner. Suspension incorporates Bilstein struts with Eibach springs, raised 19mm spindles, RSR-style gussets, and a bump steer kit up front, along with Bilstein coilovers with Eibach springs out back. Tarett Engineering sway bars are fitted front and rear.

The stripped interior houses fixed-back bucket seats trimmed in black leatherette with fabric inserts and equipped with Willans harnesses. A roll bar and microsuede headliner were added, and the dash features microsuede upper and lower pads. The doors incorporate aluminum skins and fiberglass inners, and additional equipment includes a 935-style shifter with a 917-style knob, a fire extinguisher, and a Tilton pedal set. The HVAC controls have been removed.

The microsuede-covered MOMO steering wheel sits ahead of VDO instrumentation that consists of a 180-mph speedometer, a centrally mounted 10k-rpm tachometer, and gauges for fuel level, oil level, oil temperature, and oil pressure. The five-digit odometer shows 2,300 miles since completion of the build.

The 2.9L flat-six was rebuilt during the build by Aase Motors of Fullerton, California, in 2015 using 10.5:1 compression CP pistons, 93mm Nickies cylinders, Carillo rods, AASCO valve springs and Ti retainers, and DC60 camshafts. Twin-plug cylinder heads were added at that time, and the mechanical fuel injection system features high butterfly individual throttle bodies. The engine is said to utilize an aluminum case, and additional equipment includes auxiliary front oil coolers, a 100-liter fuel tank, and jet-hot-coated Euro headers. The spark plugs, battery, and battery tray were replaced in 2025, and work in 2023 involved replacing the fuel pump and cleaning the fuel injectors.

Power is sent to the rear wheels through a G50 five-speed manual transaxle that was rebuilt and fitted with replacement synchros and a limited-slip differential during the build. Carrera rear axles were also installed.