7 Best Spark Plugs for 351W [Buying Guide 2021]

You do not only own an automobile, but you do your best to maintain it in the best possible ways. You make sure that major and minor accessories are in condition.

What about spark plugs?

They are quintessential because a vehicle will not start without it. You need it because they will ignite the fuel and air mixtures in your automobile’s cylinder walls.

Moreover, the engine in your truck or a car operates on a straightforward principle.

Best Spark Plugs for 351W

When a mixture of air and gasoline is ignited, several tiny explosions occur inside the cylinder. Your engine captures these energy-dense explosions, and it is used to drive a vehicle.

So what are the vital functions of spark plugs?

Spark plugs perform two crucial functions. Firstly, as we discussed above, they ignite the air and fuel combination to run your engine.

Secondly, they draw the heat from the combustion chamber, and they pull thermal energy away via the core nose and into the shell.

Like other vehicle parts, spark plugs also need occasional attention. You have to remove worn-out and old plugs and replace them with fresh new ones.

When plugs wear out over time, they reduce your automobile’s fuel economy, the performance suffers and damages the engine’s parts.

If you are looking for the best spark plugs for 351w, here are some of the top contenders for your engine to help it run smoothly.

We have reviewed each of these options in detail to help you out.

Let’s check these highly-rated plugs out!

Comparing 7 Best Spark Plugs for 351W

Spark PlugMaterialWeight
Autolite 3924Copper, Alloy steel1.6 ounces Check Price
Motorcraft SP-479Platinum13.1 ounces Check Price
Bosch 4504Platinum, Iridium0.8 ounces Check Price
NGK WR5 2438Nickel Alloy, Copper2.12 ounces Check Price
Autolite 25Copper, Iridium, Nickel4.8 ounces Check Price
ACDelco R42LTSCopper, Nickel1.6 ounces Check Price
Champion 406Platinum, metal1.6 ounces Check Price

1. Autolite 3924 Spark Plug – The Resistor Plugs That Works Perfectly

Autolite 3924 Spark Plug

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These medium-range copper plugs, although, are light on the pocket but they work perfectly fine. You will not regret this inexpensive purchase!

Since copper is a good conductor of heat, these spark plugs deliver superior performance and have better efficiency.

Moreover, these Autolite spark plugs come in a pack of four, and their whole copper core electrode delivers optimum performance in every condition.

Furthermore, these plugs are 100% leak-proof.

But what makes them leak-proof?

Their central electrode, terminal post, and copper glass seal bonds insulator delivers a tight seal. That does not allow these sparking plugs to leak.

What’s more!

They are engineered with precision rolled threads and cold-formed steel shells. Plus, it has a one-piece terminal post that gives additional strength.

What’s unique about these spark plugs?

They possess multi-rib insulators that minimize “flashover” danger. Moreover, they can reduce electrode erosion and radiofrequency erosion (RFI).

  • Inexpensive
  • Efficient
  • Leak-proof
  • Durable
  • It comes in a pack of four
  • Minimize electrode erosion and flashover danger
  • They may have limited longevity

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2. Motorcraft Spark Plug SP-479

Motorcraft Spark Plug SP-479

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Are your spark plugs fouled, or have they gone bad?

These plugs mimic the OEM plugs.

Plus, these pre-gapped sparking plugs come in a pack of eight, and they are all set to install them directly. They definitely improve the vehicle’s performance.

What else?

These platinum plugs require anti-seize. Plus, you have to use some oil on the threads.

Make sure to carefully apply anti-seize onto the threads and keep it off from your hands. Otherwise, it will spread everywhere.

Moreover, it is necessary to use di-electric grease inside the boots.

These high-quality Motorcraft plugs are available at a much better price than you can get at a local parts store.

What’s more!

The only drawback is that they do not come with gap adjustment tools and instructions.

And if you are a beginner, installation may take time, and you might have to adjust the gaps according to your vehicle.

  • High-quality
  • Pre-gapped
  • Optimum performance
  • Inexpensive
  • It comes in a pack of eight
  • The package does not include instructions and gap adjustment tools

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3. Bosch 4504 Fusion Spark Plug

Bosch 4504

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If you are looking for the latest spark plug technology, you should stop here! This Bosch plug is engineered by fusing iridium and platinum.

What makes this spark plug unique?

This plug is with platinum and iridium center electrode delivers an exceptional wear resistance.

It has an exclusive surface air gap firing technology that gives a more powerful and longer spark.

Due to this, it produces less stress on the ignition system. It helps the vehicle to start quickly, provides efficient fuel combustion and a more remarkable performance life.

Besides the surface air gap technology, it has four yttrium enhanced ground electrodes.

These electrodes are responsible for resisting oxidation and spark plug wear. Thus, it provides exceptional performance life.

What’s more!

Its four-ground electrode design performs better than factory iridium spark plugs. It provides the most powerful spark for the most efficient combustion.

Furthermore, this single plug comes pre-gapped. It does not require any adjustment, and it is easy to install.

Oddly enough, it is a little expensive for a single plug. Plus, it might not support a few vehicles.

  • High-quality
  • Wear resistance
  • A longer and powerful spark
  • Good performance
  • Pre-gapped
  • Straightforward installation
  • It may support certain vehicles

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4. NGK WR5 2438 – A Stellar Spark Plug for the Bucks

NGK WR5 2438

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NGK spark plugs never fail to impress! This plug is designed to improve the performance and ignitability of the vehicle.

NGK plug is reliable because it is constructed from durable material that is abrasion and corrosion-resistant.

Thus, it will not wear off quickly against chemical and electrical wear.

What’s more!

This plug is the only one that has V-groove technology. It is built according to the OEM specifications, and it can improve acceleration performance and fuel mileage.

Since it has a V-groove technology, the spark occurs at the center electrode’s edge.

The electrode does not absorb the heat, but it allows the flame to expand quickly. This ensures excellent performance.

What else? This plug contains a trivalent metal plating that offers greater longevity and durability.

Plus, the metal plating has superior anti-seizing and anti-corrosion properties. It also lowers emissions and increases the fuel economy.

Oddly enough, the only drawback users mentioned that it might not support a few vehicles that the brand has mentioned.

  • Delivers optimum performance
  • Durable
  • Corrosion-resistant
  • V-groove technology
  • Improves fuel mileage
  • Greater longevity
  • It might not support some vehicles

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5. Autolite 25 Spark Plug

Autolite 25 Spark Plug

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This product includes four spark plugs in a box. These plugs are straightforward to install, fit perfectly, and are budget-friendly.

These plugs are correctly gapped, and it will take no less than thirty minutes to install them properly.

You can use them easily for four-thousand miles, but you might have to pull them and clean them to use them further after that.

Moreover, the purpose of these spark plugs is to exceed the factory design requirements. Plus, full copper core electrodes deliver better performance in every condition.

What’s more!

They possess a one-piece terminal post that adds strength. The rolled threads are precisely made from cold-formed steel shells.

Furthermore, these ignition plugs use a copper-glass seal that bonds the insulator and terminal post center electrode together.

This ensures that plugs will receive a full voltage at the spark gap. Thus, they prove to be 100% leak-proof.

What else?

The presence of a multi-rib insulator minimizes “flashover.”

Plus, the resistors found in these plugs are responsible for reducing electrode erosion and radio frequency interference (RFI).

In short, these inexpensive spark plugs improve engine efficiency, support all vehicle models, deliver smooth acceleration, and improve fuel economy.

They might be built slightly crooked. When you thread them, you can easily see the end nearest to you wobble.

  • Straightforward installation
  • Economical ignition plugs
  • Leak-proof
  • Pre-gapped
  • Prevents electrode erosion and flashover
  • Deliver great performance
  • It may be built slightly crooked

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6. ACDelco R42LTS Spark Plug

ACDelco R42LTS

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ACDelco premium aftermarket ignition plugs are designed to fit non-GM and GM vehicles.

They manufacture each part that meets the expectations for fit, function, high-quality, and value.

Their plugs are designed for efficient and reliable performance.

Among other ACDelco spark plugs, R42LTS professional plug is a suitable, standard replacement plug that will not disappoint you.

How is this plug different from other ignition plugs?

The package will include a single plug that is black onyx coated. The purpose of this coating is to reduce corrosion.

It also has a nickel-chrome alloy sheathing that will prevent corrosion on the center electrode.

These extra protective layers on the plug do not allow it to wear and tear quickly. Thus, it offers greater longevity.

What’s more, the copper core excellently transfers heat and helps to maximize durability.

Moreover, this plug has a ribbed suppressor seal. The presence of this seal increases resistance and prevents misfires and flashovers.

Although this plug comes pre-gapped, the gap size may change due to shipment. Therefore, make sure to check the gaps before installation.

  • Delivers great performance
  • Greater longevity
  • Corrosion-resistant
  • It prevents flashovers and misfires
  • Durable
  • The gap size might change from shipment

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7. Champion RV12YC Spark Plug

Champion Copper Spark Plug

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Champion ignition plugs are US-manufactured and long-lasting.

The package includes a single plug, but it is designed to be used for various marine, small engine, commercial, and automotive applications.

What is so good about this plug? Why will it be best for 351w?

This plug has a copper core electrode that delivers heat control and increased conductivity for good overall wear.

Moreover, this electrode can accurately control heat range for greater longevity.

The plug also maximizes corrosion resistance because its shell is entirely coated with a patented ultra seal. Thus, minor corrosion means more excellent product life.

Furthermore, it dramatically suppresses RFI and EMI with the help of a patented SAC-9 semiconductor resistor.

What’s more!

This ignition plug is durable and dependable because it is built according to SAE and ISO standards.

It delivers optimum performance, consists of excellent threads, and it will provide a great fit.

The only drawback is that it is expensive for a single plug; however, it might be worth it if you are looking for a high-quality plug.

  • US-manufactured
  • Long-lasting
  • Minimizes EMI and RFI
  • Built according to ISO and SAE standards
  • Corrosion-resistance
  • Durable
  • Expensive

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Best Spark Plugs for 351W Buyer’s Guide:

Spark Plugs for 351W Buying Guide

Never underestimate the importance of these tiny vehicle parts. They are as crucial as the other parts.

An ignition plug is a small threaded metal component that contains conductive metal components separated by an electrical insulator.

This plug emits an electrical spark to ignite the combustion required to start the vehicle. So you can gather from these facts that it is a vital component.

Therefore, you need to invest in a good-quality one. Otherwise, your automobile will misfire and will be unable to deliver the smooth burn of the compressed air-fuel mixture.

Every spark plug has its pros and cons, and each brand produces a different number of plugs. Thus, the selection automatically becomes confusing.

Don’t fret! We have prepared this guide to make spark plug selection easy for you.

Before you opt for anyone, here are a few vital things and you should know about it.

Check Your Automobile’s Manual

A manual is a guide that will help you select the right kind of ignition plug. Sometimes it is best to stick with the plug you have in your vehicle.

But many times, these plugs are unavailable, and you have to go for the best possible alternatives.

A manual will help you in purchasing the perfect one that your vehicle will be able to support.

You will be able to look at the specifications to buy the high-quality factory OEM replacement spark plugs.

Thread Size

Thread size is a crucial way to specify a spark plug. If the thread size is wrong, the valve or the piston can strike it and damage the engine.

We do not want more expenses, right?

That is why thread size is of utmost importance. Thread size is also called a threaded nut.

The most popular thread size for domestic ignition plugs is 14mm. However, if you own an older Ford engine, you might need a larger 18mm thread size.

Brands or Price

Do not let the prices or brands fool you! Do not think that if it is an inexpensive product, it will fail to deliver the optimum performance and vice versa.

Each product is engineered to deliver the best performance. Some plugs might support your vehicle, while others will not.

Plus, what works for them might not work for you.

However, it does not mean settling for less. Besides jumping on to the specific brand, you should do the following.

Check the specifications, read about the product, what vehicles it supports, is the product long-lasting and corrosion resistance, is it worth the price, and what other users have to say.

By doing this, you will select the best product for your vehicle with zero regrets!

Installation Procedure

Nowadays, brands are manufacturing plugs that are pre-gapped, and they do not require adjustments.

These pre-gapped plugs are more convenient for users because they only have to open the package and install them right away.

Thus, it eliminates the fuss with the gap gauge and tool during installation.

Fixed and Adjustable Gap

There are two types of spark plugs available. You will find these plugs with either fixed or adjustable gaps.

You will see these gaps between the ground electrode or the center electrodes.

If you are buying a spark plug whose gaps need to be adjusted, you need to use a spark plug gapper tool.

A single plug is designed for several vehicles; therefore, an adjustable plug will make things easier, and you will be able to adjust accordingly.

Material Types

CopperPlatinumDouble PlatinumIridium

Copper core spark plugs are the most standard and affordable types of ignition plugs. The other variants of copper plugs are manufactured from solid copper, and they have the largest diameter.

They used to be the most common plugs in the market, but they are replaced by iridium and platinum plugs due to their increased lifespan, superior performance, and efficiency.

Modern engines do not support copper spark plugs; however, older machines do. The old vehicles perform better with copper spark plugs because they do not have excessive electrical needs.

Like copper, platinum plugs are incredibly durable, but it is not as great as iridium. Their performance and fuel efficiency are better than copper plugs.

Platinum plugs cannot beat iridium plugs, but platinum ones are budget-friendly. Like iridium plugs, these operate at a lower temperature. Plus, these plugs generate heat; thus, they minimize debris buildup.

These plugs deliver even more performance, longevity, and efficiency than single-plated platinum plugs. However, these plugs are advised for those automobiles that have a waste spark system.

These ignition plugs are cheaper than iridium ones. But if you are looking for an affordable upgrade from single-platinum plugs, you can opt for the plugs with platinum in both cap and electrode.

This material is eight times stronger and six times harder than platinum. Plus, it has a melting point of 700-degrees. It is the metal that ranks higher in terms of durability and longevity compared to platinum.

These plugs have extremely fine electrodes, but they can retain excellent wear characteristics. Due to their exceptional strength, these ignition plugs can last for about 25% longer than platinum ones.

Moreover, these plugs give you the best gas mileage, longevity, reliability, and performance than double-platinum plugs. They also require less voltage to produce the current. That’s why several users are interested in buying.

The only drawback is that it is costly, but in the end, it might be the best option for your high-performance engines.

Frequently Asked Questions:

What type of spark plugs do I require?

Even if they look similar and perform the same function, spark plugs come in a wide variety of shapes and sizes. You will have to choose spark plugs according to their physical dimensions to ensure they fit and function correctly with the automobile’s engine.

They are generally made for specific applications with exact heat ranges and physical characteristics. They also offer various features like materials for construction, electrode design, etc.

Therefore, it is best to take the help of the user’s manual. It can guide you on which spark plugs or its variation will be suitable for your model.

Do ignition plugs require extra care?

Several spark plugs do not require any special care. They are engineered to work for a given service life before being replaced or discarded.

How frequently do I have to change my ignition plugs?

The frequency of changing the spark plug varies from vehicle to vehicle. Plus, the lifespan of the spark plugs depends on numerous factors.

If you own a modern car, you might not need to change the plug frequently. You may have to after 80,000 or 100,000 miles. However, in a racing engine, you might have to change it often.

Moreover, if you have a conventional modern vehicle, you will have to change your spark plugs every few years.

In short, your manual will provide complete information on when you should change your spark plugs. Always refer to your manual when you want to change your vehicle’s parts.

Can I clean my ignition plugs?

You can clean your spark plugs, but it is not recommended. When you use a sturdy knife or a wire brush to clean your spark plugs, it lowers their efficiency.

If you really want to clean your plugs, go for spray-on plug cleaner to clean this vital component entirely.


We hope this review was detailed enough to give you an entire idea about what to buy and which one to select.

The selection process can be a mind-boggling one!

If you are still unsure about which one to purchase, go through the owner’s manual. Check the kind of spark plug your vehicle requires and its variation.

It is also crucial to look at whether these plugs you are considering buying are pre-gapped or not.

What’s more, you should ask yourself these questions as well.

What kind of material is used for their construction, is it budget-friendly, what’s the thread size, and will it support my vehicle?

This might solve your problem and help you choose the best spark plugs for 351w. We have tried to include all the best ignition plugs.

If we have missed something, please let us know! We would love to know what other spark plugs are available for 351w.

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  1. Lucky Days December 12, 2022

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