Porsche 964 3.6l engine swap for early 912 Chassis
Summary
The shop has performed multiple engine swaps over the years, placing 964, 993, 930, 3.0SC, and 3.2l engines into earlier Porsche chassis. Two 912s already converted to flat-6 power received 964 3.6l engine swaps, keeping modifications reversible where possible.
As early Porsche values have risen, these conversions require careful thought, though well-executed 'outlaw' or Gruppe R builds have sold for as much as original cars. The goal is pairing a lightweight early chassis with a 300 HP 3.6l engine for maximum driving enjoyment.
Each car receives 911 engine mounts, a 911 oil tank, 3.2l oil cooling systems, custom fuel and oil lines, correctly wired 964 ECUs, and rebuilt 915 transmissions. Most modifications can be reversed without leaving any trace.
One car uses the stock exhaust while the other gets a custom setup. Work on both 912s is ongoing.
What does a Porsche 964 3.6l engine swap into an early 912 chassis involve?
A 964 engine swap into an early 912 chassis requires welding in 911 engine mounts, adding a 911 oil tank, installing a 3.2l 911 oil cooling system, custom fuel and oil lines, a correctly wired 964 ECU, and a rebuilt 915 transmission. The result is a lightweight early car with around 300 HP.
Wiring in process
rebuilt transmission
964 oil and tach gauges are used
Fuel filter installed
Our 67 912 getting ready for 250 HP
Coils installed
We have done several engine swaps over the years, putting 964, 993, 930, 3.0SC and 3.2l engines in earlier cars. This used to make a lot of sense, but as the value of these early cars has gone up it must be considered carefully. There have been several of these :”outlaw” or gruppe R cars that have brought as much or more than original cars, but they have to be done properly. In this case we had 2 912s that had already been converted to flat 6 power, so we were not cutting up pristine early cars. Most of the modifications can be undone without any evidence they every happened. The main point of these conversions is a nice original early car is nice but a lightweight early car with a 300 HP 3.6l engine is lots and lots of fun. These cars have 911 engine mounts welded in, a 911 oil tank, 3.2l 911 oil cooling systems, custom made fuel and oil lines, correctly wired 964 ECUs and rebuilt 915 transmissions. We are using the stock exhaust on 1 and a custom exhaust on the other. Stay tuned as we progress on these cars.
FAQs
A 964 3.6l engine swap into an early 912 requires several modifications including welding in 911 engine mounts, installing a 911 oil tank, fitting a 3.2l 911 oil cooling system, and running custom fuel and oil lines. The 964 ECU also needs to be correctly wired, and the transmission - typically a rebuilt 915 unit - must be properly set up to handle the added power.
A properly built 964 3.6l engine produces around 250 to 300 horsepower, which is a massive upgrade over the original 912 four-cylinder. Paired with the lightweight 912 body, this combination makes for an extremely fast and fun car on both the street and track.
As values of early 912s have risen, this is something to think through carefully before moving forward. That said, well-executed builds - sometimes called outlaw or Gruppe R cars - have sold for as much as or more than original unmodified examples, provided the work is done to a high standard.
Most of the modifications involved in this type of swap can be undone without leaving any visible evidence that changes were ever made. This makes the conversion more appealing for owners who want to preserve the option of returning the car to a more stock configuration down the road.
Yes, starting with a 912 that has already been converted to flat-six power is a much better approach than modifying a pristine, numbers-matching car. It avoids cutting up a valuable original vehicle and still delivers the same exciting end result - a lightweight early Porsche with serious modern performance.
A rebuilt 915 transmission is commonly used in this type of swap, as it fits the early 912 chassis and can be built to handle the power output of the 964 engine. Proper rebuilding and setup of the gearbox is a key part of making the whole drivetrain work reliably together.
You can run either the stock 964 exhaust or a custom-fabricated exhaust system depending on your goals for sound, performance, and fitment. Some builders prefer a custom setup to get better clearance within the early chassis and to tune the exhaust note to match the character of the build.
