The Miata LS swap is one of the most celebrated engine conversions in the automotive world, offering a dramatic leap in power while keeping the iconic Mazda roadster’s lightweight charm. But dropping a V8 into a car never designed for it demands more than just the engine and adapter mounts. Without properly matched supporting modifications, the added horsepower and torque can quickly overwhelm the chassis, driveline, and cooling system. In this guide, we focus on three critical areas that will make or break your LS-swapped Miata: upgraded cams to extract optimal power from the engine, heavy-duty radiators to manage heat soak in a cramped engine bay, and a reworked suspension to tame the new weight distribution and power delivery. Whether you’re building a street bruiser or a track-day weapon, these components are the foundation of a reliable, thrilling build.

Upgraded Cams: Unlocking the LS Engine’s True Potential

The LS family of V8 engines is known for its torque-rich character and aftermarket friendliness. Even a stock LS can transform the Miata, but a performance camshaft is one of the highest‑value upgrades for increasing airflow, horsepower, and throttle response. Swapping cams changes the valve timing and lift, allowing the engine to breathe more freely at high RPMs without sacrificing low-end drivability if the profile is chosen wisely.

Why Upgrade the Camshaft in an LS‑Swapped Miata?

While the LS produces ample power in stock form, its cam profile is a compromise designed for fuel economy and emissions in full‑sized trucks or sedans. In a lightweight Miata, you can optimize for performance. An upgraded cam lets you:

  • Increase peak horsepower and torque – Gains of 30–60+ hp are common with a well‑matched cam and supporting tune.
  • Improve throttle response – Faster valve opening ramps sharpen engine reaction to pedal input.
  • Shift the powerband upward – Many LS cams move the torque peak higher, which suits the Miata’s lighter weight and higher RPM usage.
  • Create a distinctive exhaust note – More aggressive overlap produces the classic muscle car lope.

For a Miata LS swap, the goal is usually a broad, usable power curve rather than an all‑out top‑end scream. That means a mid‑range performance cam (often called a “stage 2” or “street/strip” cam) works better than a radical race grind.

Several aftermarket camshaft manufacturers offer grinds specifically suited to street‑performance LS swaps. Here are three reliable choices:

  • Texas Speed Stage 2 Cam – With around 224/228 duration at .050” lift, this cam provides fantastic mid‑range punch and still drives well on the street. It’s often paired with a set of long‑tube headers and a good intake to gain 40–50 hp.
  • Brian Tooley Racing (BTR) Stage 3 Cam – More aggressive (227/235), this cam pushes the powerband higher and makes excellent top‑end power. It requires a higher stall converter if paired with an automatic, but in a manual‑equipped Miata it rewards aggressive driving.
  • Comp Cams XFI – The XFI series is designed for fast‑ramp profiles, reducing valve float risk while still delivering strong gains. A 224/230 XFI cam offers a nice balance of idle quality and peak power.

Whichever cam you choose, always pair it with dual valve springs, hardened pushrods, and updated lifters to handle the increased stress. A professional tune is non‑negotiable after a cam swap to dial in the fuel and spark tables.

Installation Considerations

Installing a cam in an LS engine while it’s already in the Miata engine bay is possible but tight. Access to the front timing cover requires removing the radiator, fans, and sometimes the front sway bar. If the engine is out of the car during the swap, it’s the ideal time to upgrade the cam. Many builders also replace the oil pump and timing chain while they’re in there, as those parts are cheap insurance.

Upgraded Radiators: Keeping the V8 Cool in a Tiny Engine Bay

The Miata’s engine compartment was never meant to fit a V8. After an LS swap, the available space for a radiator shrinks dramatically, and the engine generates significantly more heat. Overheating is the number one killer of LS‑swapped Miatas that lack proper cooling support. A high‑performance radiator is not an option—it’s a necessity.

Why the Stock Miata Radiator Won’t Cut It

The original Miata radiator is sized for a 1.6L or 1.8L four‑cylinder engine producing around 100–140 hp. An LS engine can produce 300–500+ hp, with correspondingly higher heat output. The tight front clip also limits the core thickness and fin area. Without an upgrade, you’ll see coolant temperatures climb during spirited driving, leading to knock, reduced power, or catastrophic head gasket failure.

Radiator Options and Key Features

When shopping for a radiator for an LS‑swapped Miata, look for these attributes:

  • All‑aluminum construction – Aluminum transfers heat more efficiently than the original copper/brass and is lighter.
  • Increased core thickness – A dual‑pass or cross‑flow design maximizes cooling capacity in limited space.
  • Larger tank volume – More coolant means better heat absorption and slower temperature rise.
  • Integral or included electric fans – Because the engine‑mounted fan will not fit, a high‑CFM electric fan setup is essential.

Top recommendations from the Miata LS swap community include:

  • Griffin Aluminum Radiator – Griffin offers custom sizes and core thicknesses that can be ordered to fit the Miata’s narrowed radiator support. Their dual‑pass models are popular for track use.
  • Mishimoto Performance Radiator – Mishimoto makes a specific Miata radiator that many LS swap builders modify to fit. It features a welded aluminum core and a shrouded fan assembly.
  • CSF Racing Radiator – CSF’s “V8 Miata” radiator is designed from the ground up for LS swaps, with a thicker core and relocated inlet/outlet ports to clear the engine.

Supporting Cooling Upgrades

Even the best radiator needs help. Consider these complementary mods:

  • High‑output electric fans – Spal or Flex‑a‑lite fans with a thermostat controller keep airflow high at low speeds.
  • Aluminum radiator shroud – A custom shroud ensures all fan airflow passes through the core, not around it.
  • Coolant reroute – LS engines suffer from uneven cooling; a thermostat relocation and rear cooling mod can drop temperatures by 10–20°F.
  • Ducting and sealing – Seal all gaps between the radiator and body to force air through the core, not around it.

Proper coolant mixture (70% water, 30% antifreeze with a wetting agent) also improves heat transfer. Many high‑performance builders run distilled water with a bottle of Water Wetter for maximum cooling efficiency.

Suspension Upgrades: Taming the V8’s Power and Weight

The LS swap adds roughly 150–200 pounds over the front axle compared to the original four‑cylinder. This shifts the Miata’s weight distribution forward (from ~50/50 to about 52–54% front) and significantly increases the car’s center of gravity if the engine sits high. Without suspension upgrades, the car will understeer, dive under braking, and feel unstable in corners. A reworked suspension transforms the swapped Miata into a balanced, confidence‑inspiring machine.

Why Suspension Matters More After an LS Swap

The increased power demands better control of body motions. Heavy acceleration causes the nose to rise, reducing steering authority; hard braking with the added weight can overwhelm stock dampers. Additionally, the LS engine’s torque can unsettle the rear end if the suspension isn’t dialed. Upgraded springs and dampers keep the tires planted, allowing you to use the extra power effectively.

Coilover Kits: The Foundation of Control

Coilover shocks replace the Miata’s separate spring and shock design with a single, threaded unit, allowing ride height and spring preload adjustment. For LS‑swapped cars, choose a coilover with:

  • Higher spring rates – Front springs of 500–700 lb/in and rear of 350–450 lb/in are typical for a V8‑powered Miata.
  • Rebound and compression adjustment – This lets you fine‑tune damping for street comfort or track grip.
  • Monotube construction – Better heat dissipation and consistent damping than twin‑tube designs.

Popular choices include BC Racing Coilovers (BR series with custom spring rates available) and Flyin’ Miata Fox Coilovers (designed with higher rates for boosted or swapped cars). BC Racing is especially popular because they offer Swift spring upgrades and remote reservoirs for track‑focused builds.

Upgraded Sway Bars and Bushings

The extra front weight calls for stiffer sway bars to control body roll and reduce understeer.

  • A hollow front sway bar (1.125” or 1.25” diameter) provides roll stiffness without adding much weight.
  • A proportionally stiffer rear bar helps rotate the car on corner entry. Many LS‑swapped Miatas run a 5/8” rear bar or an adjustable unit.
  • Polyurethane bushings in the sway bar mounts and control arms eliminate slop and provide consistent response.

Race Engineering and SuperMiata offer swirl‑polished or adjustable sway bars that allow fine‑tuning. Replace all rubber bushings with polyurethane (Energy Suspension or Moog) for sharper turn‑in and better steering feedback.

Alignment and Corner Balancing

After installing coilovers and sway bars, a professional alignment is essential. For a street/track dual‑purpose LS Miata, a typical alignment is:

  • Front camber: –2.5° to –3.0°
  • Rear camber: –1.5° to –2.0°
  • Front toe: 1/16” total toe out
  • Rear toe: 1/8” total toe in

Corner balancing the car with driver weight ensures that all four wheels carry equal load, maximizing grip. A good suspension shop can adjust ride heights individually to achieve a 50/50 cross weight.

Other Key Supporting Mods to Complete the Build

While cams, cooling, and suspension are the stars of this article, a complete LS swap also benefits from upgrades in several other areas:

  • Fuel system – A Walbro 255 lph or higher in‑tank pump, larger injectors, and a return‑style regulator are needed for high‑horsepower builds.
  • Brakes – The extra weight and speed demand bigger brakes. Wilwood or Flyin’ Miata Big Brake Kits are common upgrades.
  • Clutch – A twin‑disc clutch from ACT or McLeod handles the LS’s torque without excessive pedal effort.
  • Driveshaft and differential – Strengthened axles and a limited‑slip differential (often from a Ford 8.8” or Mazda RX‑7) prevent driveline failure.

These components integrate with the three main areas we’ve covered, ensuring a cohesive, reliable build.

Putting It All Together

The Miata LS swap is an incredible transformation, but its success depends on thoughtful upgrades to a few critical systems. Upgraded cams unlock the V8’s power potential, a high‑performance radiator guards against heat soak, and a reworked suspension tames the new weight and torque. By prioritizing these three areas, you create a car that is not only brutally fast but also dependable and composed. Start with a solid plan, budget for quality parts, and remember that a well‑tuned package always outruns a collection of mismatched components. Whether you’re chasing lap times or carving back roads, these supporting mods will turn your Miata LS swap into a masterpiece of engineering and driving pleasure.