1973.5 Porsche 911T Type 911/91 Engine – Original 2.4L Flat-Six with Bosch CIS Injection

A highly desirable Type 911/91 2.4-liter flat-six originally built for a US-market 1973.5 Porsche 911T. This numbers-correct magnesium-case engine retains its Bosch CIS fuel injection, ignition setup, alternator, cooling system, heat exchangers, and muffler. According to the seller, the engine was running when removed approximately twelve years ago and has been stored indoors since—a strong foundation for restoration, rebuild, or a period-correct concours installation.

Factory Specification & Technical Details

• Engine Type: 911/91

• Displacement: 2,341cc

• Bore x Stroke: 84mm × 70.4mm

• Application: US-spec 1973.5 Porsche 911T (CIS introduction year)

• Case Material: Magnesium

• Case Stamping: ☆6133837☆ (correct for 1973.5 911T engines)

Included Components

• Bosch CIS Fuel Injection System

  • Fuel distributor

  • Stainless-steel CIS airbox by Webb Machine Design

• Ignition System

  • Distributor

  • Spark plug wires

  • Coil

• Cooling System

  • Eleven-blade fan

  • Alternator

  • Engine tin finished in black

  • Fan shroud

• Exhaust System

  • Heat exchangers

  • Muffler

• Driveline Components

  • Flywheel

  • Clutch

Condition & Suitability

• Engine was running when removed ~12 years ago

• Stored indoors since removal

• Ideal candidate for:

  • Period-correct 1973.5 911T restoration

  • CIS-specific vintage Porsche projects

  • Engine builders seeking an untouched 2.4L core

  • Collectors sourcing a matching-era drivetrain

The 1973.5 911T marked Porsche’s transition to Bosch CIS fuel injection, making the 911/91 engine unique in the 2.4L lineup. Its combination of a magnesium case, mechanical refinement, and CIS reliability makes it a sought-after powerplant among early G-body enthusiasts.