There is no single best engine swap for every Mazda Miata. A Honda K24 is a strong general-purpose choice for a naturally aspirated build when a generation-specific package is available; a GM Ecotec suits a torque-focused NA or NB project; LSx and LFX conversions target V8 or V6 builds; and a Mazda 13B is for drivers who specifically want rotary character. The right choice depends just as much on your Miata’s generation, drivetrain, budget, fabrication capacity and local rules as it does on the engine.
Compare the main Miata engine-swap options
This is a qualitative shortlist, not a dyno-tested ranking. The comparison guide and supplier pages establish that certain conversions are marketed or supported; they do not prove comparative reliability, street legality or performance in every chassis.
| Swap | Best suited to | What the available evidence supports | Key tradeoffs |
|---|---|---|---|
| Honda K24 | A broadly useful naturally aspirated build where conversion support matters | KPower lists K24A2 and K24Z3 packages for NA/NB Miatas, NC-specific products, and an ND kit announcement. Its catalog identifies chassis-specific offerings. | Confirm the package fits your exact model year, and plan for the donor engine, ECU and wiring, transmission strategy, differential capacity and the full conversion cost. |
| GM 2.4L Ecotec LE5 | A torque-oriented NA or NB project | EcotecMiata sells a dedicated Miata conversion and ECU. Its current page marks several featured products out of stock; availability may change. | Check current inventory and get a written list of what the specific kit includes before committing. |
| GM LSx / LS3 V8 | A power-first or V8-character build | Exomotive says it worked with V8Roadsters on Exocet LSx kits. Its FAQ also names other V8 options. | Plan for chassis integration, traction, cooling, driveline strength, cost and legal requirements. Evidence for an Exocet kit is not proof of fitment in every road-going Miata. |
| GM LFX V6 | A V6 conversion in the documented Exocet context | Exomotive identifies an Exocet-specific LFX V6 kit developed with V8Roadsters. | Confirm the exact donor chassis and kit documentation; the cited information does not establish universal fitment in every Miata configuration. |
| Mazda 13B rotary | A builder seeking rotary character and Mazda lineage | Lucky 7 Racing describes a kit for installing a second-generation 13B in a first-generation Miata. | Verify that exact engine and chassis combination. Rotary-specific heat, oiling, tuning, fuel consumption, donor supply and maintenance all affect the ownership plan. |
| Ford 2.3L EcoBoost | An advanced custom or competition fabrication project | The cited comparison guide describes it as a plausible modern turbo candidate, but does not establish an off-the-shelf Miata conversion kit. | Expect a less-documented path than the K24 or LE5. Direct injection, electronics, packaging, heat management and the stated off-road-use warning need to be addressed. |
Choose for your goal, not a horsepower number
For a supported four-cylinder route: Honda K24
The K24 is the most reasonable default if you want a naturally aspirated four-cylinder conversion and your generation has a package that actually fits. KPower’s separate NA/NB, NC and announced ND offerings show why “K-swap Miata” is not a single universal parts list. The best-supported option on paper is still the wrong choice if its package, electronics or transmission plan does not match your car.
For a torque-oriented NA or NB: GM Ecotec LE5
The Ecotec is a credible alternative when the target is a torque-focused build rather than a particular brand of engine. The dedicated conversion and ECU are useful signs of a defined path, but the current out-of-stock notices make a direct stock and included-parts check essential before planning around it.
Crashes, No Sound, or Screen Glitches?
Random freezes, missing sound and display glitches usually trace back to one bad driver. Find and replace yours safely.Free scan · under a minutePC Slower Than It Used to Be?
A free scan shows the junk files, broken settings and background clutter dragging Windows down - then fixes them in one click.Free scan · Windows 10 & 11#1 Best Overall
- [Specification] 1pc 1PIN front coolant switch sensor connector with a 15 cm lead.
- [Compatibility] Compatible with Mazda Miata 1990-1993 models requiring a 1PIN front coolant switch sensor connection.
- [Functionality] Provides a stable path between the coolant switch and vehicle wiring harness to transmit accurate sensor signals for engine cooling system monitoring.
- [Material/Construction] Made from quality plastic housing and metal terminals to deliver reliable conductivity, corrosion resistance, and durability in automotive environments.
- [Easy Installation] Standard 1PIN connector and 15 cm lead allow straightforward plug-in installation into the existing sensor wiring without modifications.
For V8 or V6 character: LSx or LFX
LSx and LFX conversions make sense when the engine configuration and intended power are central to the project. The clearest cited supplier evidence is for Exocet builds: Exomotive identifies its collaboration with V8Roadsters for LSx and LFX kits, and also names K-series, J-series and other V8 options in its FAQ. An Exocet is a Miata-based conversion; those listings do not establish that the same parts install in an unmodified Miata.
For a rotary-specific build: Mazda 13B
The 13B route is for someone who values rotary character enough to accept its distinct service and tuning needs. Lucky 7 Racing’s stated application is narrow: a second-generation 13B in a first-generation Miata. Do not extend that fitment claim to an NB, NC or ND.
Rank #2
- Over time, the black plastic cover may age or become lost, allowing a large amount of water to enter the engine compartment. In some cases, it can even get into the interior fuse box. With this easy-to-install black plastic cover, you can prevent this situation.
- Compatible with Mazda MX-5 Millenia MPV MX-3 Protégé Protege 5 RX-7 Eunos 3 BK Cowl grille caps（Please see Figure 4 for details）
- Compatible with Ford Probe Laser etc （Please see Figure 4 for details）
- Part Number:E016-50-796,BP4M-50-705, 107-D036
- Installation: Simply pop out the original black oval-shaped cover on one end of the windshield cowl. Clean the area around the hole and then fit it back in. Pop in the new black cover and repeat the process on the other side! (The old one often cracks when removed)
For a custom turbo project: Ford 2.3L EcoBoost
The EcoBoost is better treated as a custom fabrication project than as a straightforward kit alternative on the evidence available here. The cited guide flags direct-injection electronics, packaging and heat, and does not establish a ready-to-install Miata package.
Start with the Miata generation and exact year
The comparison guide frames the generations as NA (1990–1997), NB (1998–2005), NC (2006–2015) and ND (2016 onward). Treat those ranges as a guide, then verify your specific model year and market. Packaging, electronics, transmission arrangements, subframes, steering clearance, emissions equipment and drivetrain relationships can differ. An NA/NB product listing does not demonstrate NC or ND compatibility.
The Tool Desk
Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Rank #3
- This Gates Engine Coolant Thermostat Housing Gasket is compatible with Mazda Miata 2004, 2003, 2002, 2001, 2000, 1999, 1998, 1997, 1996, 1995, 1994, 1993, 1992, 1991, 1990 1.6L 1.8L L4
- Genuine Gates Parts
- Includes original packaging and hardware
- Direct replacement auto parts
- Confirm vehicle fitment with Amazon Confirmed Fit
- NA and NB: KPower lists K24A2 and K24Z3 packages for 1990–2005 cars; EcotecMiata sells a dedicated Ecotec conversion; and Lucky 7 Racing specifies its 13B kit for a first-generation car. Check each package’s current contents and exact fitment.
- NC: KPower lists NC-specific products separately. Do not infer that an NA/NB kit, installation price or parts list applies to an NC.
- ND: KPower promotes an ND K-swap kit, but an announcement alone does not establish its detailed fitment, contents, delivery time or emissions status. Check the product and installation documentation.
- Exocet conversions: Exomotive’s FAQ addresses 1990–2005 Miata-based Exocet conversions. Its cited engine options are evidence for that conversion context, not a blanket fitment statement for a complete, unmodified Miata.
Budget the complete conversion, not just the engine
A long block or advertised kit price is not an installed total. Before choosing an engine, ask the supplier for a written bill of materials that identifies included and excluded parts and labor. The following systems can determine whether a nominally attractive swap is practical:
- Engine mounts, oil pan and clearance to the chassis, steering and subframe
- Transmission, clutch, driveshaft, differential and axles
- ECU, wiring, sensors and calibration
- Fuel delivery, cooling and exhaust
- Brakes and suspension appropriate to the finished car
- Fabrication, troubleshooting and any inspection, registration or insurance work
Ask whether the build can retain air conditioning and power steering, whether it requires a different transmission or differential, and who is responsible for wiring, calibration and exhaust fabrication. The available supplier information does not provide a uniform, complete bill of materials across swaps, so there is no substantiated universal installed price.
Rank #4
- 【Vehicle Fitment】PHILTOP Engine Mount Transmission Mount Kit Compatible With Mazda 1990-1993 Miata 1.6L, 1994-1997 Miata 1.8L, 1999-2005 Miata 1.8L
- 【OEM Number】PHILTOP Engine Motor are manufactured in accordance with OE standards. Replace OE Number# A4400, 8909
- 【Package Included】PHILTOP Engine Motor Mount Transmission Mount Torque Strut Mount Set Package Included: 1x Front Left Motor Mount +A4400/8909, 1x Front Right Motor Mount + A4400/8909
- 【High Performance】The engine mounts are made of natural rubber and metal materials, adapting to cold, high temperature and extreme environment of the engine compartment. Improve NVH performance, reduce high-frequency vibration 20-200Hz, reduce vehicle vibration amplitude by about 70%, and reduce cockpit noise by 5-10 db, able to withstand extreme environments of -40℃ and 120℃.
- 【Installation Instructions】: 1. Align all bolts; 2. Gently screw the bolts into the holes; 3. Tighten all bolts simultaneously(Do not tighten them one by one). The heat shield can be bent for easy installation, but be sure to clean the adhesive in the installation area before installation and restore any bent areas from disassembly to a flat state.
What KPower lists for packages and installation
KPower’s live catalog and installation page showed the following figures when accessed October 4, 2026. Catalog prices are not installed totals, and KPower’s installation figures are labor charges, not a complete all-in conversion price.
| Listing | Published figure | Scope and qualification |
|---|---|---|
| K24A2 NA/NB ultimate package | $6,395 | KPower catalog price; check current availability and package contents. |
| K24Z3 NA/NB ultimate package | $4,595 | KPower catalog price; check current availability and package contents. |
| NA Miata turn-key installation | $5,950 | KPower labor charge; the page specifies a Haltech Elite 1500 ECU, drive-by-wire and supporting electronics. It excludes possible extra work. |
| NB Miata turn-key installation | $5,450 | KPower labor charge; the page specifies a Haltech Elite 1500 ECU, drive-by-wire and supporting electronics. It excludes possible extra work. |
| NC Miata turn-key installation | $3,950 | KPower labor charge with a Haltech Elite 1500; it is not a complete installed conversion price. |
These figures are specific to KPower’s listed products and services, not a fair head-to-head price comparison with the other swaps. Reconfirm current prices, package scope, availability and what additional parts or work your car needs before using them in a budget.
Best Value
- [Vehicle Fitment]: CA12075 Compatible with Mazda MX-5 Miata 2016-2025; Fiat 124 Spider 2017-2020
- [3-Stage Progressive Density Media]: At the core of the PT engine air filter is an advanced nanofiber hybrid media, engineered for unrivaled performance. The outer layer traps large debris, the middle layer reduces fine dust, and the inner safety layer blocks ultra-fine particles. This multi-stage process guarantees exceptionally clean airflow, providing the highest level of protection for your engine's critical components
- [Improved Fuel Economy]: Cleaner intake air improves the efficiency of the fuel combustion process, which improves fuel economy and reduces emissions. A well-maintained air filter is critical to environmental protection and economical driving
- [Installs in 5 minutes]: OE design for direct installation. No special tools or modifications required. Self-installation is easy and convenient
- [Suggestion for Replacement]：Replace every 12 months or when it drives to 12,000 miles. If you often drive in heavily polluted areas and muddy roads, it is recommended that you replace them frequently to keep the air fresh in the car
Check road-use rules before buying parts
Legality depends on where the car will be registered and how it will be used. KPower states that its swaps are intended for off-road use only and places responsibility for local laws on the customer. That statement does not establish whether another supplier’s package is road legal. Before purchase, check your jurisdiction’s inspection and emissions rules, title and registration requirements, and insurance conditions for an engine conversion.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
