Best Spark Plugs For 6.4 Hemi

Spark plugs are responsible for the spark that burns the petrol-air mixture. This process creates combustion that produces power for the engine.

Getting the right spark plug could be the difference in your engine’s performance. Below, you’ll find the best spark plugs for the 6.4 Hemi.

The NGK 6510 LTR7IX-11 Iridium IX spark plug is the best spark plug for the 6.4 Hemi. The melting point of the Iridium is very high; it is tough and provides a reliable spark. This spark plug is made for engines to perform up to their potential.

3 The Best Spark Plugs For 6.4 Hemi

#1. NGK 6510 LTR7IX-11 Iridium IX spark plug

This NGK spark plug is first on the list for the 6.4 Hemi. The presence of three chemical valence metal coating gives it a high anti-corrosion attribute.

The trivalent coating also makes it a good conductor of heat. It is highly durable, with about 40,000 to 50,000 miles of service.

You can purchase the LTR7IX-11 Iridium IX spark plug here:

#2. NGK 97408 LZTR6AP11EG Laser Platinum Spark Plug

This Platinum spark plug is also one of the best spark plugs for the 6.4 Hemi. This spark plug offers great ignitability and a lengthy period of service.

Two platinum surfaces are laser fused. This surface offers enhanced petrol efficiency and a lesser rate of emissions.

The LZTR6AP11EG Laser Platinum Spark Plug can be bought here:

#3. NGK 6509 LTR6IX-11 Iridium Spark Plug

This Iridium spark plug is another great alternative for the 6.4 Hemi.

An expertly designed electrode in this spark plug guarantees amazing durability and a reliable spark.

The heat transfer is also great and features a copper core to help in heat removal. The LTR6IX-11 Iridium Spark Plug can be purchased here:

What Spark Plug Does Dodge Recommend?

To have a sophisticated and pleasing driving experience, Dodge has recommended the following spark plugs;

#1. Mopar Chrysler Jeep Dodge Spark Plugs Mopar

This spark plug is a great option that offers greater mileage for your vehicle. This amazing kit features original spark plugs.

The triple seals stop leakage and have durable materials. You can purchase this spark plug here.

#2. Bosch Automotive 8162 Double Platinum Spark Plug

This spark plug works well with an engine in a high-performance vehicle. It doesn’t lag as it hastily starts the vehicle, makes it run faster, and quickly responds.

This plug has a platinum piece laser welded to provide a triple service period.

In addition, these plugs don’t need gap alteration before installation as they are gapped at the factory. You can purchase this spark plug here.

#3. NGK LZFR5C-11 Spark Plug

This spark plug from NGK can provide the ideal spark required for the engine to start.

Three chemical valence metal layers give it a further anti-corrosion attribute.

In addition, it has grooved ribs to avoid flashover and pure alumina silicate ceramic padding for enhanced heat transmission. You can buy this spark plug here.

#4. NGK 2262 Spark Plug ZFR5F-11

This spark plug can develop your Dodge’s MPG (mile per gallon). This plug has trivalent metallic gilding with a core Copper material that makes it resilient to corrosion.

The trivalent coating also ensures optimum heat transfer. You can buy this spark plug here.

#5. Spark Plug NGK 5463 BKR5EIX-11 Iridium IX

This iridium spark plug will last for a good while with optimum performance. It features a slim stout tip that helps throttle sensitivity.

It is highly reliable and a good option for the Dodge. You can purchase this spark plug here.

#6. Champion Spark Plug RE14MCC4 570 Copper Plus

This type is a copper spark plug. It is a very reliable plug that offers the right heat control to last long.

The copper core elevates the plug’s operation and is plated with TinTac and Ultra-Seal shell.

This plating is just enough to prevent corrosion of the plug. You can purchase the plug here.

#7. Champion 3570 Platinum Power Spark Plugs

A second Champion spark plug means they have incredible performances. This spark plug is made out of Heat-Active alloy.

The V-shaped electrode also offers a precise spark.

The middle wire’s end is coated with platinum to withstand wear and retain the right gap spec during usage. You can purchase this plug here.

#8. ACDelco Professional Iridium Spark Plugs 41-993

This Iridium spark plug is gapped to the right gap requirement at the factory.

This is a good Dodge spark plug as this promises quality performance even for other vehicles.

It features a fine electrode design that is dependable for cold starting and fast spurts. You can purchase this plug here.

#9. Autolite AP5263 Platinum Spark Plug

A middle platinum firing point offers enhanced performance and longevity. The platinum point also guarantees no gap corrosion.

Its necked-down middle electrode fires faster with precision and less voltage for calmer starts. You can purchase this plug here.

Do Better Spark Plugs Increase Horsepower?

Although new spark plugs do not exactly increase horsepower, they give it that boost for the ideal combustion level.

In addition, when you replace your old spark plug with new plugs, there’s quicker engine responsiveness during driving. 

Spark plugs perform the task of igniting the petrol-air combination in the combustion compartment.

As a result, a worn-out spark plug will adversely affect the vehicle’s gas mileage.

This situation increases the demand for additional power so the engine can keep running. A fresh spark plug won’t have this problem.

Using old and damaged spark plugs also result in engine misfires. Further, this leads to a 30% decrease in petrol economy for your vehicle.

An old spark plug also incurs additional costs to maintain the vehicle and fuel top-ups.

The absence of a sharp spark to properly combust the petrol-air mixture will require more petrol to ignite. That’s why it’s important to replace them periodically.

In addition, worn and old spark plugs mount some pressure on the engine.

New spark plugs are suitably gapped when installed, meaning they’ll operate at maximum power. That means there’ll be fewer emissions to worry about. 

Also Read: Does Hyundai Warranty Cover Engine Replacement?

How Often Should You Change Hemi Spark Plugs?

Replacing spark plugs in Hemi engines depends on the model year. For example, the 5.7L Hemi engine spark plugs need replacing after 30,000 miles.

This time frame was the standard until 2004 when the period for replacement stretched to 100,000 miles.

The 6.1L Hemi V8 engine and the 6.4L engine need new spark plugs after 96,000 miles.

The 6.2L modified Hemi V8 engine also needs replacement plugs after 60,000 miles. You don’t need to exhaust these miles before changing your spark plugs.

However, be alert for signs like slow acceleration, sounds from the engine caused by a misfire, and rough idling.

You can replace the spark plugs before any serious issue develops if you pay close attention.

Furthermore, spark plugs must be on equal performance levels to get the ideal combustion.

One good plug among bad plugs cannot carry the weight of performance. It makes the engine unsynchronized in operation.

It is therefore important to replace all the Hemi spark plugs simultaneously. If you change individual plugs, it’ll be bad for your engine and proves to be time-consuming.

In addition, you should do an engine checkup regularly since different spark plugs have varying service life.

There are different spark plugs for different Hemi engines. There’s the standard thread type and the tapered thread design.

Fixing or attempting to fix the incorrect plug might damage the cylinder head’s thread and even the plug. 

Spark plugs should also possess similar electrical resistance. Resistance values vary between 3,500 – 20,000 ohms.

Make sure to check resistance using a 1,000-volt tester and not an ohmmeter. Ohmmeters don’t usually give correct readings.


The NGK 6510 LTR7IX-11 Iridium IX spark plug is the best spark plug for the 6.4 Hemi.

Replacing spark plugs depends on the year and model of the engine, as they have individual replacement intervals.

It is advisable to examine spark plugs periodically for any damage or underperformance. 

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