1973 Porsche 911S Type 911/53 Engine and Five-Speed Transaxle

Presented here is a Type 911/53 flat-six engine paired with a five-speed manual transaxle, originally built for a 1973 Porsche 911S delivered new in Santa Clara, California. The engine, stamped ☆6332035☆, confirms its origin as a U.S.-market 911S powerplant. This unit represents Porsche’s final and most refined version of the mechanically fuel-injected (MFI) 2.4-liter S engine — a high-performance specification that produced 190 horsepower when new.

The engine was rebuilt in 1979 with 2.2L 911S pistons, slightly altering compression and response. Approximately a decade later, it was installed in a 1970 Porsche 911T, where it received further maintenance, including the addition of Carrera-specification timing chain tensioners during the mid-to-late 1990s. The seller, who acquired the car in 1998, removed both the engine and gearbox for long-term storage, during which oil was periodically circulated to maintain internal lubrication.

Although the engine turns freely, it is offered as a core for rebuild. Recent servicing included removing the valve covers to lubricate camshaft lobes and valve train components and adding oil to the cylinders. Several wear issues are noted, including chipped fan impellers, noisy alternator bearings, rusted heat exchangers, a chipped hot air regulator horn, dry fuel and vacuum lines, and cracked CDI wiring insulation.

Technical Specifications

• Engine Type: 911/53

• Engine Stamping: ☆6332035☆

• Displacement: 2,341cc (2.4 liters)

• Configuration: Flat-six, air-cooled, rear-mounted

• Bore x Stroke: 84mm x 70.4mm

• Compression Ratio: Originally 8.5:1 (modified with 2.2L 911S pistons)

• Fuel System: Mechanical Fuel Injection (Bosch MFI)

• Power Output (factory rating): 190 hp @ 6,500 rpm

• Torque (factory rating): 159 lb-ft @ 5,200 rpm

• Valve Train: SOHC per bank, chain-driven, 2 valves per cylinder

• Block Material: Aluminum

• Head Material: Aluminum

Condition & Work Performed

• Rebuilt: 1979 (fitted with 2.2L 911S pistons)

• Carrera Tensioners Installed: Mid-to-late 1990s

• Stored Since: 1998 (oil periodically circulated)

• Condition: Engine turns freely but requires full rebuild

• Recent Maintenance:

  • Valve covers removed for lubrication

  • Oil added to cylinders

  • Cam lobes and valve train pre-lubed

Noted Defects:

• Chipped fan impellers

• Noisy alternator bearings

• Rusted-through heat exchangers

• Chipped hot air regulator horn

• Brittle fuel and vacuum lines

• Cracked CDI wiring insulation

Transaxle

• Type: 5-speed manual

• Condition: Used, removed from vehicle during storage

• Compatibility: 1970–1973 911 models with 915-series transmission mounts

Included Components

• Type 911/53 2.4L flat-six engine (core)

• 5-speed manual transaxle

• MFI system (complete but aged)

• Alternator and cooling fan assembly

• Heat exchangers (rusted)

• CDI ignition unit and harness (aged)

• Valve covers, flywheel, clutch

• Fuel and vacuum lines

Compatibility

• Factory-correct for: 1973 Porsche 911S (U.S. specification)

• Also compatible with: 1972–1973 911T / 911E chassis with appropriate mounts and MFI configuration.

Ideal for restoration, period-correct rebuilds, or early 911S projects seeking a matching-specification Type 911/53 power unit.