1973.5 Porsche 911T Type 911/91 Engine – 2.4L Flat-Six – CIS – Engine Number ☆6133837☆

This Porsche Type 911/91 2.4-liter flat-six engine is a correct and highly desirable powerplant originally built for a US-market 1973.5 Porsche 911T. Representing the first model year of the 2.4-liter 911 engines, the 911/91 is historically significant as Porsche’s transition to Bosch CIS (Continuous Injection System) fuel injection, combining improved drivability with period-correct engineering.

The engine retains its original Bosch CIS fuel-injection system, ignition components, cooling hardware, and exhaust equipment. According to the seller, the engine ran when removed approximately twelve years ago and has been properly stored since, making it an excellent candidate for recommissioning or a full professional rebuild. The engine case stamping ☆6133837☆ and visible 911/91 type marking confirm authenticity and correct application for a US-spec 1973.5 911T.

Specifications

• Engine Type: Porsche Type 911/91

• Configuration: Air-cooled flat-six

• Displacement: 2,341cc (2.4L)

• Bore x Stroke: 84mm x 70.4mm

• Case Material: Magnesium

• Original Application:

  • US-market 1973.5 Porsche 911T

• Fuel System: Bosch CIS (Continuous Injection System)

• Cooling:

  • Eleven-blade cooling fan

  • Black fan shroud and engine tins

• Ignition: Distributor, spark-plug wires, ignition coil

• Engine Number: ☆6133837☆

• Rebuild Status: Not rebuilt; stored since removal

Included Components

• Bosch CIS fuel injection system

• Fuel distributor

• Webb Machine Design stainless-steel CIS airbox

• Alternator

• Cooling fan and shroud

• Heat exchangers

• Muffler

• Flywheel and clutch assembly

This high level of completeness makes the engine especially attractive for restorers seeking a correct, largely intact CIS setup.

Condition & Notes

• Engine ran at time of removal (approx. 12 years ago)

• Stored indoors since removal

• Not currently running or tested

• Sold as a recommissioning or rebuild candidate

• All major components remain installed and intact

• Original magnesium case with correct stampings documented in gallery

Ideal Applications

• 1973.5 Porsche 911T US-spec restoration

• Period-correct CIS-equipped engine rebuild

• Matching-era replacement engine for collector cars

• Porsche engine collectors and vintage specialists

Why This Engine Matters

• Correct Type 911/91 designation for 1973.5 US-market 911T

• Authentic Bosch CIS system retained, increasingly difficult to source complete

• Original magnesium case with verified stamping ☆6133837☆

• High completeness reduces sourcing costs for restoration

• Important transitional engine in 911 history

This Porsche Type 911/91 2.4L flat-six is a compelling opportunity to acquire a historically significant, largely complete early CIS engine with documented provenance—ideal for concours-level restoration or collector investment.