The Honda K-swap is the modern darling of Miata engine swaps: drop a revvy, reliable K20/K24 into an NA/NB and get 200-plus naturally-aspirated horsepower in a light chassis. Purpose-built kits (KMiata, KPower) have made it genuinely achievable.
The K-series is a fantastic engine, strong, high-revving, well-supported, and it suits the Miata's character better than a heavy V8 for a lot of people. A stock K24 makes N/A power the Miata could never make on its own.
- What it is: A Honda K20 or K24 with a proper swap kit, adapter plate/flywheel or a Honda transaxle solution, subframe, mounts, oiling, intake/header, and wiring/ECU conversion.
- Who makes it work: KMiata and KPower sell engineered kits that solve the subframe geometry, mounts, oiling, and wiring, this is what took the K-swap from one-off fabrication to a repeatable build.
- Power: Stock K24A2 commonly makes 220-plus whp naturally aspirated, more with cams/head work or boost, in a car lighter than the Hondas these engines came in.
Practical realities:
- Cost: Budget roughly low-five-figures in parts for a DIY build (kit, engine, supporting bits), plus tuning and any shop labor. Cheaper than a V8, still a real project.
- Fitment quirks: A K24 sits taller than a K20 and may need hood clearance work on an NA. Plan cooling, shifter, and axle details.
- Tuning: Standalone or Honda-based management and a proper tune are part of the job.
Who it's for: the enthusiast who wants naturally-aspirated, high-revving power and modern reliability without the weight and cost of a V8. It's more involved than a turbo kit but rewards you with a completely transformed, sonorous, screaming Miata. For a lot of builders, it's the sweet spot of the swap world.