Spark plugs are one of the essential parts of your ignition system. Without them causing sparks to ignite the fuel, your engine wouldn’t be able to produce power, and you simply wouldn’t have a running vehicle. But not all spark plugs are the same.

They are usually quite durable, but eventually, you will need to replace them. Good quality spark plugs cost a little extra but are more durable and give you excellent throttle response, providing consistent power, which is essential for a Mustang V6.

If you have one of these cars, then your engine deserves the best. Here we take a look at the best spark plugs for Mustang V6.

Best Spark Plugs for Mustang V6

Here you will find information about the three best spark plugs for a Mustang V6. You also will get to know a little more about the properties of spark plugs and when you might need to replace them. Let’s start with our recommendations!

1. E3 Spark Plug E3.74 Automotive Copper Spark Plug

E3 Spark Plug E3.74 Automotive Copper Spark Plug
E3 Spark Plug E3.74 Automotive Copper Spark Plug

Made with a Diamond Fire electron technology, these reduce the travel time from the spark to the combustion gases. As a result, you can get a potential doubling of power, and significant fuel

efficiency improvement, depending on your engine. The superior alloy steel covering provides the E3 spark plugs with the ability to prevent carbon deposits, resulting in a significantly longer lifespan for these plugs.

The center electrode on E3 spark plugs consists of nickel alloy with a copper center core for better conductivity and heat dissipation.

They also come with a five-year/or 100,000-mile limited manufacturer warranty.

Pros and Cons


  • Provides a proven steady improvement in acceleration  
  • Maximizes energy conversion while reducing fuel consumption        
  • More reliable conductivity compared to similar plugs


  • Not compatible with all engine sockets

2. Autolite XP5363-4PK Iridium XP Spark Plug

Autolite XP5363-4PK Iridium XP Spark Plug

The Autolite spark plugs have an Iridium-enhanced platinum alloy 0.6mm fine center electrode for improved ignition, guaranteeing smooth engine performance. The platinum side design also makes sure the spark plugs resist wear, and no gap erosion occurs for long periods of use.

These are not only the best value for your money but super easy to install and pre-gapped, which is perfect if you need their exact gaping for your vehicle. Although they are not hard to re-gap, you can check your fit before purchasing for a seamless installation process. It’s no wonder they earned a near-perfect score from satisfied customers.

Pros and Cons


  • Noticeable smoother engine performance that lasts longer
  • A price that is hard to beat for the value of the product
  • Highly erosion-resistant platinum construction of whole plugs


  • Often need refitting of gaps

3. E3 Spark Plugs E3.74 Spark Plug

E3 Spark Plugs E3.74 Spark Plug
E3 Spark Plugs E3.74 Spark Plug

14mm reach plugs that fit a wide variety of vehicle engine model applications. The patented Diamond FIRE electrode in the shell is kept secure with three different legs. This way, the heat transfer becomes more powerful, while the turbulence in the cylinder is amplified.

The side wire increases power, significantly reduces fuel consumption, and improves hydrocarbon emissions.

The unique, full-size center electrode also provides optimal engine function and far better mileage, especially in older models or hybrids. The superior performance has a guarantee of five years or 100,000 miles.

Pros and Cons


  • Reduced fuel consumption per mile and more power
  • Better chance for compatibility with your engine type
  • Engine runs smoother due to more efficient heat transfer


  • The price includes 1 plug, while some pictures show a package of 4

Best Mustang V6 Spark Plugs – Buying guide

While all three of these models work with a Mustang V6, there are slight differences among them. Your choice of plugs can depend on various factors, such as price, gaping, or material.

The Autolite XP5363-4PK Iridium XP is definitely the most cost-effective one of the three. If you want a high-quality platinum spark plug that grants a smooth engine performance and is affordable, this is the right choice for you.

If you want to make sure that your spark plug has the best conductivity and is more resistant to erosion caused by carbon deposits, you should opt for the copper-centered E3 E3.74 Automotive Spark Plug.

Finally, for a money-saving, reduced fuel consumption, extensive compatibility, more fluid engine performance certified by customers, and increased power in the motor overall, pick the E3 E3.74 Spark Plug.

Benefits of spark plugs

Since their invention in 1902, high voltage spark plugs became a fundamental part of the subsequently developed spark-ignited engines. As their name already suggests, these plugs emit small sparks creating the ignition for the combustion needed to start your vehicle. Putting the pistons in motion, the engine powers up and burns the compressed air-fuel mixture.

Spark plugs that withstand extreme heat and pressure within the cylinders are meant to burn off deposits from fuel additives or other contaminants.

The health of them directly affects your engine’s performance. Weakened plugs can lead to severe problems, such as cold-starting or misfiring during acceleration. This will not only mean that you won’t be able to get maximum power or suffer engine damages. A malfunctioning spark plug also increases fuel consumption, which is certainly not beneficial for your budget on a long-term basis.

Spark plug types

The classification of spark plugs usually depends on their material. Thus, the most common metal types of plugs are copper, iridium, platinum, and double platinum. Different metal spark plugs can offer increased fuel efficiency, better engine response, smoother idle, and easier starting.

They also come in different sizes according to their corresponding pockets and the size of the engine, varying from 3/4 inches to 13/16 inches. According to their heat range, spark plugs can be low heat range or hot and high heat range or cold.


Copper spark plugs – This spark plugs coat is mostly made from copper, a material known for being highly resistant to erosion by rust. However, its central electrode is made from nickel alloy, which is soft and not very durable. This means it probably wouldn’t last long, so it’s best to use copper spark plugs in older vehicles that don’t have high electrical needs.

The copper spark plugs have the largest diameter of all the spark plugs, meaning that they’ll need more voltage to generate an electric current. Usually used in older vehicles, where it’s not worth using a pricier spark plug, or in engines specially designed for copper spark plugs.

Iridium spark plugs – Iridium spark plugs are known to last the longest, as iridium is a metal that is harder and even more durable than platinum. Although they are higher price category, the performance will most certainly justify the price, and you will get what you pay for.

The iridium spark plugs have a small center electrode, using less voltage to generate the electric current. Many car manufacturers are starting to install exclusively and recommend only iridium spark plugs for their vehicles.

If you need to replace your iridium spark plugs, only do it with the same kind. Otherwise, your engine’s performance and lifespan will suffer.

Platinum spark plugs – Single platinum spark plugs are similar to the copper ones, except their center electrode has a platinum disc welded to the nickel alloy in its tip area. As a result, the platinum spark plug is more durable, lasting as many as 100,000 miles or 5 years, which is often guaranteed by the manufacturer.

These plugs also generate more heat, which means that they burn more debris, avoiding erosion caused by carbon deposits. Single platinum spark plugs are highly recommended both for and by every new car owner with an electronic coil-on-plug ignition system.

Double platinum spark plugs – Double platinum spark plugs have a platinum coating both in the center and around the ground electrodes, making them far more efficient, not to mention longer-lasting. They are the best choice for a wasted spark ignition system, which causes more wear on electrodes than the other engine ignition systems.

This happens because each ignition coil fires two spark plugs at once, one in the compression and the other in the exhaust cylinder. Since these ignition systems, powered by a double-platinum spark plug, aren’t affected by rain or debris, they can last three times longer than those with a standard copper spark plug.


If you’re searching for the perfect spark plug for your current project, pay special attention to the hex size required. The plug socket determines the plug’s hex size you will need for installation. The manufacturer often provides it so that you won’t buy the wrong one by mistake. You should know the diameter of the cylinder head moreover the thickness of the plug socket needed for installation.

5/8″ are the most used plug sizes for smaller vehicles, while most larger, older ones require a 13/16″ spark plug. 7/8″ is employed in aviation, agricultural vehicles, motorcycles, and 3/4″ in lawnmowers and smaller engines.

Heat range

The heat that the electrode of the spark plug receives during combustion is dispersed, and the degree to which a spark plug distributes the heat is called its heat range. The dispersing ability is essentially determined by the gas temperature inside the combustion chamber and the spark plug’s design.

Low heat range spark plugs have long insulator legs with the surface area affected by the flame, plus the gas capacity is quite large. The longer heat release path from the insulator to the housing is causing heat the temperature of the center electrode to rise quickly.

Meanwhile, high heat range plugs have shorter insulator legs, meaning the surface area that’s engulfed by the flame and the gas pocket capacity is smaller. The heat dispersal is higher due to the short insulation leg, and the temperature of the center electrode will rise slower.

Gap style

The spark plug gap is the area between the center and the ground electrode, and this is where the plug’s spark discharge is designed to take place. This area is generally the closest point between the spark plug center electrode and the spark plug ground electrode. The only case when the spark will travel longer is when the longer path is more conductive.

Most manufacturer spark plugs are preset to a gap around 0.75mm – 0.8mm, but many of those will need adjustment. For better engine and spark plug performance, the size, style, and shape of the spark plug gap should be compatible with the ignition system, the pressure in the combustion chamber, the type and concentration of the fuel or the engine load, and its intended use.


For older Ford vehicles, standard nickel alloy spark plugs are more than acceptable, even according to the manufacturer. For most newer models, an extended platinum tip spark plug is recommended.

A Ford Mustang with a 4L V6 engine has a set of six spark plugs. These plugs are specifically designed as a direct fit for the 2006 to 2010 Mustangs.

Yes, they do. Especially if you have newer vehicles or engines whose lifespan you want to extend. Iridium spark plugs last up to 120.000 miles while giving your vehicle a more reliable spark.

Technically, the two most important details in a spark plug are matching the design of your engine. As the larger brands usually make more durable and reliable spark plugs, they do matter.

The most common signs of a spark plug that needs a replacement are a rattling noise, the car having trouble starting, the inability to accelerate efficiently, and worsening fuel economy.

It depends on the type of spark plugs you have installed. The copper spark plug will need replacement between 30.000-50.000 miles, platinum plugs at around 80.000-100.000 miles, while the iridium ones can go over the 120.000 milestones.

Best spark plugs: Conclusion

In conclusion, it could be said that as spark plugs are an essential part of any engine with internal combustion, you will need to take good care of yours. An engine usually requires multiple spark plugs, but the failure of only one can cause a lot of internal damage to your vehicle if it’s neglected.

If you require a replacement, you will have a couple of options to choose from unless limited by the manufacturer. Your choice will depend mostly on your budget or your willingness to invest in the durability of your engine.