Runge Engineering Finished New Flat-Eight Crate Engine
Owners of 1974 to 1989 Porsche 911s can now consider a 5.3-liter engine upgrade that fits existing chassis.
Updated on Oct. 11, 2026 in Performance Vehicles
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Runge Engineering has completed dyno testing on a new air-cooled flat-eight crate engine designed for 1974 to 1989 Porsche 911 chassis. The unit allows owners to install a racing-inspired engine configuration never offered by the factory for production road vehicles.
Why it matters
This engine brings a 917-inspired flat-eight design to classic Porsche owners who want to increase performance without altering the structural integrity of their vehicle's chassis. It provides a specialized alternative for those looking to modernize their vintage powertrain.
The engine features a 12:1 compression ratio and 32 valves, with performance data and final pricing expected in December 2026. For reference, past bespoke engine projects from similar builders have reached $250,000 in development and manufacturing costs.
The players
Runge Engineering
A Minnesota-based firm specializing in bespoke, high-performance air-cooled engine manufacturing.
Porsche
A German automaker known for its rear-engine 911 sports car and historic dominance in endurance racing.
The details
The engine architecture draws heavily from the Porsche 917 flat-eight design used in endurance racing. It is engineered to bolt directly into the G-body engine bay of 1974 to 1989 Porsche 911s, avoiding the need for firewall modifications. The design utilizes dual overhead cams per bank and an air-cooled cooling system.
Timeline
1970 and 1971: The Porsche 917 won the Le Mans endurance race.
1974 to 1989: The production run of the Porsche 911 G-body chassis.
December 2026: Scheduled release of horsepower, torque, and pricing figures.
The Home Front
The introduction of this flat-eight crate engine follows the trend of aftermarket firms developing specialized performance units for legacy luxury vehicles. It marks a departure from standard restorations by offering configurations that were previously unavailable to the consumer market.
If you own a 1974 to 1989 Porsche 911, ensure you have your original engine documentation and vehicle history files ready for review. Consult with a specialized air-cooled technician to determine if this crate engine configuration meets your project goals before the final pricing release in December.
The takeaway
This flat-eight engine provides a rare opportunity to install a racing-derived powertrain in a classic Porsche without invasive chassis modifications. Owners interested in this project should calendar December 2026 to review the official power outputs and pricing details.
What happens next
Runge Engineering will release final performance specifications and pricing for the 5.3-liter flat-eight engine in December 2026.
Further reading
For more on high-performance engine upgrades, visit Performance Vehicles.
Live Poll
Would you pay a premium price for a custom, performance-focused engine swap for your classic car?
