Breaking The Rules: 4 Controversial Porsche 911 Engine Swaps That, Actually Work

Porsche 911 (997) Chevrolet LS3 Swap

As far as engine swaps go, most people will not judge you for going with Chevy’s V-8 engine from the LS series. The LS3 is a great all-rounder since it packs more baseline power than the iconic LS1 while being more reliable (out of the box) compared to the bigger LS7. This proven platform is the mill of choice for Chavis Performance Engineering (CPE), who specialize in getting rid of the problematic flat-six engines, found on most Porsche 996 and 997.1 Carrera models.

This is also a cheaper alternative to an engine rebuild from Porsche themselves and an easy way to get extra power. Think of it this way, at least it is not a classic, air-cooled Porsche 911 with a Tesla swap. In terms of figures, you get roughly 240 extra horsepower with the LS swap - for a total of 495 - while having 40 fewer pounds on the rear axle.

Porsche 911 (997) Honda K20-swap

This second build caught my attention for being a four-cylinder. Honda is mostly known for its bullet-proof, inline-four engines, capable of handling big horsepower numbers. Nick from Tuning by Nick, decided to avoid, potentially, expensive repairs on his 2006 Porsche 911 Carrera S by swapping the 3.8-liter boxer engine, with 190,000 miles on it, for a Honda Civic Si, K20 unit with 56,000 miles. Honda’s K-series engines are known for three things – being able to produce big power reliably, having great aftermarket support, and being affordable (still).

This Japanese four-banger is also known for having incredible thermal efficiency while the top-end can cram as much air as you need, making it perfect for turbocharged applications. After the swap (and a few mods), the car puts out 435 wheel-horsepower, which is 135 more than the standard engine. The owner’s goal is 500 horsepower to the wheels. To add to the madness, this Carrera S has been visually transformed into a 997 GT3.

Porsche 911 (997) GT3 Subaru EJ25 Swap

When it comes to boxer engines, Subaru’s EJ25 is known to be a hit or miss. So, why on earth would a reputable outfit like DevSpeed put one in a 997 GT3? It turns out there is a good reason why the Porsche 911 (which was a rolling chassis before the project) got the Subaru engine. The man behind the build, professional drifter and car builder, Faruk Kugai, said that the reliability issue of the Subaru has been sorted. While not nearly as iconic as Porsche’s boxer engine, the EJ25 has been fully built and now features a closed-deck block, which gives much-needed rigidity when pushing high horsepower figures.

In this case, power is set at 550 horsepower. Donning Subaru’s iconic blue colors and the yellow start, the car was first seen at the 2022 SEMA Show and features a custom wide body, reminiscent of the RSR model, as well as a fully 3D-printed interior with roll-cage welded directly to the bodywork. The reasoning behind choosing the EJ25 instead of the typical Chevy LS V-8 swap is the center of gravity, which remains identical to the stock car’s.

Porsche 911 Mazda 13B REW Rotary Swap

Perhaps the most extreme swaps of the cars I’ve listed here, Purists will go mad over this one. This unique build involves a 1966 Porsche 911 that used to have an air-cooled flat-six, which according to the current owner and builder, was beyond repair. He decided to go mad and do a rotary swap, which is hardly the most reliable platform to go with. Actually, it is the least reliable. Nevertheless, the twin-rotary mill that once powered a1996 Mazda RX-7 FD found a new home in this classic Porsche that now features a Speed Yellow exterior with a subtle hint of Green pearl.

The engine has been fully built to handle up to 690 horsepower. Custom bodywork includes 993 and 964 bits, along with, get this, a Mazda RX-7 sunroof. The owner lives to piss off Porsche purists and Corvette owners. If you want to find out more about this crazy 911 rotary build, you can read more about it here.