How Many Spark Plugs Do A 5.7 Hemi Engine Have?

A spark plug is a device used to deliver electric current from the ignition system to the combustion chamber.

Its main function is to ignite the compressed fuel or air inside the chamber. Spark plugs also relieve heat from the combustion chamber to the cooling system.

This device is a necessity for your 5.7 Hemi engine. Spark plugs completely enhance an engine’s performance by providing extra power to the combustion chamber. So, if you have faulty plugs, it will compromise the potential of your engine.  

Now, maybe you’re wondering how many spark plugs you need for a single-engine and what spark plugs fit it. Worry no more. This article will answer that for you and provide you with the list of the spark plugs model you’ll need.

What Is A  5.7 Hemi Engine?

A 5.7 Hemi engine is a 90-degree V8, 2-valve pushrod constructed like earlier Magnum series engines. It is manufactured by Chrysler, one of the biggest automobile companies in the US. A Mechanic Insider article said it’s a third-generation Chrysler’s V8 Hemi engine.

For the specifics, the 5.7 Hemi engine has an aluminum cylinder head material and a cast-iron cylinder block. The 5.7 Hemi engine requires 16 spark plugs for a smoother and improved experience.

Compared to older models, this version also has a flatter design and squish shelves on both sides to reduce emissions. This feature also helps in increasing engine efficiency. The 16 spark plugs also contribute to these two mentioned benefits.

The 5.7 Hemi engine is also incorporated with MDS (Multi-Displacement System), a cylinder deactivation system. It works to save fuel and emission reduction for a more eco-friendly approach.

Upon its release, the 5.7 Hemi engine has undergone various changes and remodeling through the years.

The most notable change in the 5.7 Hemi engine was the addition of Variable Valve Timing or VVT. This customization aims at better “volumetric efficiency” and improved “breathing under a wide variety of conditions.”    

Buying Guide To Spark Plugs 5.7 Hemi

Making a list of considerations before buying spark plugs for your 5.7 Hemi engine is essential. You have to make sure that what you choose will fit the 5.7 Hemi versions that you have.

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The following factors provided below will guide you in choosing the perfect spark plugs for your 5.7 Hemi engine:  

Engine Compatibility

In choosing spark plugs for your 5.7 Hemi engine, the manufacturer’s recommendation is the best option to follow. This specific engine requires specific spark plugs. So you have to follow your car’s preference more than yours.

The compatibility between the spark plugs and the engine is crucial. If overlooked, it might affect the overall performance and damage your engine.

Ease Of Replacement

If you’re not an expert or it is your first time replacing spark plugs, getting the original parts is advisable. This move will spare you the hassle of going through complex installation and mechanisms.

However, if you’re already used to changing spark plugs to your 5.7 Hemi, make sure that the parts always fit. Never forget to match the model of your engine to the plug replacements.

Gap Style  

Most spark plugs are constructed to fit a wide range of engine types. But, there are still some that work for a specific engine alone.

Thus, it would be best to be cautious, especially with the proper gap excess. The gap between electrodes is crucial as it dictates the stability of the engine.

It ensures that proper voltage occurs for fuel ignition and combustion generation, which assists in the engine’s running. For the 5.7 Hemi engine, the optimum gap is 0.43 inches.


According to Replicar Club, one of the crucial factors in choosing is a thread size that suits the engine’s needs. If the reach of the thread is too short, carbon deposits can build up and create holes in the spark plug.

The spark will also not properly ignite if the size does not match. There are 10mm, 12mm, 14mm, 16mm, 18mm of thread sizes to choose from.  

Spark Plug Type

To properly decide what spark plugs to use, you must know their types and characteristics. There are three famous spark plugs: copper, platinum, and iridium.

Copper Spark Plug

This type of plug is considered the most famous among the three. Copper is known for its high conductivity and temperature stability, which plugs need to possess.

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However, copper lacks the strength and durability to withstand for a longer time. Hence it is used for earlier engine versions.

Iridium Spark Plug

Iridium is the most sturdy and durable material for a spark plug among the three. It has great qualities and features for longer use and benefits.

The iridium spark plug induces further longevity and requires less voltage amplification.

Platinum Spark Plug 

The metal platinum is proven to be robust, so using it as core material for a spark plug guarantees durability. Platinum spark plugs can hold high temperatures and heat stress resistance.

The Auto Artist also pointed out that platinum spark plug “also helps to prevent unwanted deposits or buildup occurrences.” There is also double platinum in the market, which gives a longer life span.


The 5.7 Hemi engine needs 16 spark plugs for maximum potential optimization, except for the latest or newer versions.

Your 5 Best Options For 5.7 Hemi Spark Plug

Sometimes, even though you already have a guide, it can still be confusing. Yes, you know what features to look for in a product. However, similar specifications are present in almost all brands.

With tons of options available online and at your local markets, the need for more digging is necessary. Thus, this article already compiles your best spark plug options for the 5.7 Hemi engine.

If you want to see what product would seal the deal for you, keep on reading.

1. NGK (4469) LFR5AIX-11 Iridium IX Spark Plug (8 Pack)

This spark plug’s core material is iridium, the best choice for high-performing engines. The iridium base of NGK IX Spark Plug has also been its best selling point.

Compared to other platinum and element, iridium is considered one of the strongest materials. Thus, it can live longer than most spark plug brands.

The 0.6-millimeter laser welded Iridium tip also ensures an increase in throttle responsiveness. Also, the NGK IX Iridium Spark Plug guarantees high durability and stable spark.

Replicar Club also noticed the longer insulator of this spark plug, which prevents the nose from fouling. Furthermore, the insulator prevents flashover, and “a triple gasket seal eliminates combustion gas leakage.”

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The NGK IX Iridium Spark Plug’s mentioned features make consumers applaud this spark plug. This specific model has been their go-to part for their engine maintenance.

2. Mopar Chrysler Jeep Dodge Spark Plugs Mopar

Unlike the previous model, the Mopar Chrysler Jeep Dodge Spark Plugs core material is nickel. This type of spark plug is said to be one of the best fits for the 5.7 Hemi engine.

The Mopar spark plug has a dimension of 4.2x4x3.7 inches and weighs 2 pounds. It was first available in the market in 2014. Since then, people have started patronizing this Mopar Jeep Dodge spark plug.  

With its great quality and robust build, you can guarantee that you have a long time before replacing your spark plugs. Mopar also has a feature to make your engine more responsive to the transmission downshift.  

The neat and safe packaging of this Mopar Jeep Dodge spark plug is also a great plus for many customers. Just a little reminder, always check first if the plug works on your truck. The Mopar is the best fit to dodge ram 1500 5.7 Hemi.

3.  ACDelco 20 Professional RAPIDFIRE Spark Plug

This ACDelco 20 Professional RAPIDFIRE provides great heat transfer with pure copper as its core material. It also helps in bringing the plug durability’s maximum potential.

A solid-state suppressor paired with a two-piece glass and brass seal also helps reduce radio frequency interference. This ACDelco 20 Professional RAPIDFIRE also has a feature that regulates spark energy for long electrode life.

In addition to these innovative features, this spark plug also aids in protecting the engine against high combustion pressures. A ribless insulator is also improved to optimize the plug to boot seal.

The ACDelco 20 Professional RAPIDFIRE is also produced to fit the engine of the general motor. So this spark plug might be your best choice if you need something specific.

4. Bosch Automotive 8162 Double Platinum Spark Plug

This 8162 double platinum spark plug parades itself as one of the best in the market right now. Indeed, Bosch is considered a brand that has set the standard for spark plug technology. Their innovative and performance-proven products helped them build a name in the industry.

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Going to the Bosch Automotive 8162 Double Platinum spark plug specifics, one key feature is its double-platinum base. Compared to a normal platinum material, a double-platinum can make the spark plug perform 3x longer.

This Bosch flagship spark plug also uses precious metals to perform better than any platinum-coated tool. A 360-degree continuous laser-welded center electrode is also meticulously placed to increase durability.

For reliable ignition, Bosch Automotive 8162 has an OE fine wire design to reduce the voltage, affecting the engine’s ignition. An OE-matched spark position also helps in customized compatibility.

5. Autolite Platinum Spark Plug

Last on the list is the Autolite Platinum spark plug. A full platinum tip ensures no gap erosion for long plug life. This spark plug’s core and top material combined nickel and alloy steel.

Various elements are also enhanced in this Autolite Platinum, like yttrium and high nickel alloy side electrode, to maintain a specific gap. These enhancements also contribute to the plug’s sturdiness.

For the physical appearance, it is slightly lighter than other spark plugs, weighing 8.4 ounces with 3.38x1x1 inches dimension. Autolite Platinum is also one of the new spark plug models as it was first available in 2018.

The product also received praises for its quicker acceleration, easier starts, and improved fuel economy. The installation of this Autolite Platinum spark plug is also hassle-free.

Frequently Asked Questions (FAQs):

What Does HEMI Stand For?

HEMI is a shortened version of the word “hemispherical.” This term relates to engines that have hemispherically shaped combustion chambers.

Motor Trend further explained that the Hemi chamber’s characteristics and shape contribute to the engine’s performance. The Hemi structure produces a “more rapid rise in combustion chamber pressure than a typical overhead valve design.”

Why Does The 5.7 Hemi Have 16 Spark Plugs?

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A 5.7 Hemi engine comprises two valves per cylinder requiring two spark plugs. The first two spark plugs work to solve the emission problems of Chrysler’s older engines. Meanwhile, the other two plugs initiate flame to guarantee complete combustion.

In simpler terms, each cylinder of the 5.7 Hemi engine has two spark plugs each to ensure that the car gets complete combustion. The spark plugs also help in fuel-saving and emission reduction.

Also, the main goal of having more spark plugs in a 5.7 Hemi is to aid the planet’s problems. The 16 spark plugs ensure that the engine will produce cleaner emissions.

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Do All 5.7 Hemi Have 16 Spark Plugs?

Yes, if you have the earlier version of the engine since it is standardly built with 16 dual-combustion. However, some cars with upgraded engine efficiency no longer require 16 spark plugs.

How Often Should You Change Spark Plugs In A 5.7 HEMI?

Based on Mopar’s maintenance chart, changing spark plugs should be done every 10 years or when your car has traveled 160,000km. But, it’s always best to check the spark plugs from time to time to ensure that it’s in good condition.

You also have to note that spark plugs have different lifespans depending on the materials and manufacturer. Thus, you should be knowledgeable about the state of your spare spark plugs.

How Long Will 5.7 HEMI Last?

The 5.7 Hemi engine can last up to 200,000 to 300 000 miles on average. When it’s well maintained and properly checked up, it can go above those numbers.

Takeaway on 5.7 Hemi Spark Plugs

The functionality of your 5.7 Hemi engine heavily depends on the quality of the spark plugs. Thus, when faulty plugs start to show, make sure to choose only the best and most fitting plugs.

Do not reconsider getting the expensive yet most compatible with your engine. Again, the optimization of the performance of your engine relies on spark plugs. So, it will all be worth the penny and research.

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