7 Best Spark Plugs For 6.4 Hemi Reviewed in 2025

When you own a powerhouse like the 6.4L Hemi, you know the ignition system is critical—and since these engines run a twin-spark setup, choosing the right 16 plugs matters immensely for performance and fuel efficiency. I spent some time researching and testing options to find the Best Spark Plugs For 6.4 Hemi that really deliver reliable power, whether you’re towing a heavy load or just enjoying the highway. Getting that consistent, powerful spark is key to keeping the engine running smooth and strong, and a quality set of plugs is non-negotiable for maximizing your Hemi’s potential.

IMAGE	PRODUCT NAME	AMAZON LINK
	16 pc NGK Iridium IX Spark Plugs compatible with Ram…	View on Amazon
	16 pc NGK Iridium IX Spark Plugs compatible with Ram…	View on Amazon
	NGK Set of 16 Iridium IX Spark Plugs For Chrysler…	View on Amazon
	Autowxjq Iridium Spark Plug 16pcs Replace Chrysler Dodge…	View on Amazon
	16 pc Champion Copper Plus Spark Plugs compatible with…	View on Amazon
	NGK Laser Platinum Spark Plugs Compatible with Chrysler…	View on Amazon
	AIP Electronics Dragon FIRE Performance Ignition Coils &…	View on Amazon

16 pc NGK Iridium IX Spark Plugs compatible with Ram 2500 5.7L 6.4L V8 2011-2020

NGK’s Iridium IX line is often the benchmark for performance upgrades, and this 16-pack is specifically designed for Ram 2500 owners looking for reliability and improved throttle response. Iridium is significantly harder than platinum, giving you outstanding durability and a consistent spark over a long service life. These plugs are a straightforward, genuine NGK solution that fit right into your 6.4L V8 engine without complex modifications, offering a substantial upgrade from standard copper plugs.

Key features that stand out:
– Genuine NGK Parts: Assurance of quality engineering and fitment.
– Iridium Construction: Provides high durability against heat and electrical wear.
– Direct Replacement: Designed to match OE specifications for hassle-free installation.

Pros:
– Excellent resistance to fouling and misfires.
– Noticeable improvement in cold starts and idle smoothness.
– Superior longevity compared to traditional plugs.

Cons:
– Premium price point due to Iridium material.

Best for: Hemi owners seeking a proven performance upgrade with great long-term reliability in Ram 2500 trucks.

Expert Opinion: This plug offers an optimal balance of cost and performance longevity. The Iridium IX is a smart choice for daily driving and light hauling, ensuring the demanding twin-spark system operates efficiently.

16 pc NGK Iridium IX Spark Plugs compatible with Ram 1500 5.7L V8 2011-2024 HEMI V8 truck

While specifically compatible with the 5.7L V8, the Iridium IX technology offered in this kit applies equally to performance requirements of the 6.4 Hemi where applicable. This set focuses heavily on spark efficiency and reducing environmental impact through better combustion. If you are experiencing minor misfires or feel your current plugs are causing unnecessary emissions, this NGK set is engineered to bring back crisp ignition timing and full combustion power.

Key features that stand out:
– Advanced Electrodes: Designed to minimize spark gap growth over time.
– Improve Ignition and Spark Efficiency: Promotes complete combustion for better mileage.
– Durable Shell: Reliable protection ensuring long-lasting sparking capabilities.

Pros:
– Helps significantly reduce frustrating misfires.
– Designed by NGK NTK, a world leader in ignition systems.
– Robust construction guarantees performance consistency.

Cons:
– Need to verify specific 6.4L fitment carefully as the primary focus is 5.7L.

Best for: Drivers prioritizing reduced emissions and achieving the most efficient combustion possible from their Hemi engine.

Expert Opinion: The focus here is on precision ignition. For high-mileage 6.4L engines, the design elements minimizing gap growth are crucial for maintaining high-end power delivery.

NGK Set of 16 Iridium IX Spark Plugs For Chrysler Dodge Jeep Ram 5.7 6.4 V8

This is the generalized NGK Iridium IX set built to service the full spectrum of 6.4L and 5.7L V8 applications across the Chrysler, Dodge, Jeep, and Ram lineup. If you’re looking for a simple, standardized upgrade that provides maximum coverage and a reliable spark, this 16-piece kit is an excellent choice. It’s a popular option among DIY mechanics because of its wide compatibility and trusted quality standard.

Key features that stand out:
– Wide Hemi Compatibility: Fits various models including Charger, Challenger, and 300C with the 6.4L engine.
– Iridium Tip: Ensures a precise and concentrated spark.
– Proven NGK Performance: Known for resistance to oxidation and wear.

Pros:
– Extremely reliable performance across various Hemi platforms.
– Excellent cold-weather starting capabilities.
– Great upgrade path from standard factory plugs.

Cons:
– May require professional installation due to the quantity (16 plugs).

Best for: Hemi owners needing a standard, high-quality Iridium replacement that fits multiple vehicle types within the Mopar family.

Expert Opinion: When in doubt about specific fitments, a comprehensive kit like this one offers peace of mind. Iridium plugs consistently provide the cleanest spark for the Hemi’s dual ignition system.

Autowxjq Iridium Spark Plug 16pcs Replace Chrysler Dodge Jeep Ram 4.7L 5.7L 6.4L V8

If you’re looking for the benefits of Iridium without the premium price tag of a major brand name, this Autowxjq set provides an attractive alternative. A huge convenience factor here is that these spark plugs are advertised as being pre-gapped, allowing for immediate installation right out of the box—though you should always verify the gap for your specific engine. They boast a high melting point, making them tough enough to handle the thermal demands of the high-performance 6.4 Hemi.

Key features that stand out:
– Iridium Design: High melting point ensures durability in high-performance engines.
– Pre-gap: Conveniently gapped and ready for immediate installation (check gap before installing).
– Warranty: Comes with a 2-year warranty and free replacement.

Pros:
– Highly budget-friendly entry point for Iridium technology.
– Pre-gapped design saves installation time.
– Strong warranty coverage provides confidence in the product.

Cons:
– Longevity may not match established OE brands like NGK or Champion.

Best for: The value-conscious shopper who wants the conductivity and durability of Iridium without breaking the bank.

Expert Opinion: While not an OEM brand, the Iridium core provides excellent performance characteristics suitable for the 6.4 Hemi. For drivers who change their plugs more frequently, the cost savings here are substantial.

16 pc Champion Copper Plus Spark Plugs compatible with Ram 2500 5.7L 6.4L V8 2011-2019

Champion Copper Plus plugs are the traditional workhorse choice and often a favorite among enthusiasts who prefer high conductivity and don’t mind shorter replacement intervals. Copper offers the best electrical conductivity of all plug materials, delivering a powerful, immediate spark. Although they wear out faster than Iridium or Platinum, the initial performance boost and lower cost per plug are huge factors for many Hemi owners who like to perform maintenance frequently.

Key features that stand out:
– Genuine Champion parts: Backed by a long history in racing and OE manufacturing.
– Copper Core: Provides superior conductivity for a stronger initial spark.
– OE Quality: Direct replacement auto parts adhering to tough industry standards.

Pros:
– Excellent spark energy and immediate throttle response.
– Very cost-effective for a 16-plug change.
– Highly trusted brand with great OE fitment.

Cons:
– Requires replacement significantly sooner than Iridium or Platinum options.

Best for: Performance enthusiasts and those who change plugs frequently, prioritizing maximum conductivity and initial spark strength over longevity.

Expert Opinion: Copper is the standard for raw power delivery. If you plan to heavily modify or frequently track your 6.4L Hemi, the high conductivity of copper is a measurable advantage, provided you stick to a stringent maintenance schedule.

NGK Laser Platinum Spark Plugs Compatible with Chrysler Dodge Jeep 6.4L Hemi V8 with Twin Spark Ignition System (16 Pack)

When it comes to longevity and manufacturer reliability, these NGK Laser Platinum plugs are hard to beat. NGK is the actual Original Equipment (OE) manufacturer for many Hemi applications, and this Platinum set is built to meet or exceed those stringent factory standards. The biggest draw is the impressive 96,000-mile service interval—if you want to install your plugs and forget about them for years, Platinum is the material of choice.

Key features that stand out:
– Actual OE Manufacturer: Ensures perfect fitment and function, meeting factory requirements.
– Laser Platinum: Provides exceptional heat resistance and erosion protection.
– Long Service Interval: Recommended replacement at 96,000 miles.

Pros:
– Outstanding durability and plug life.
– Maintains gap accuracy over extremely long periods.
– Guaranteed high performance, meeting OE specifications.

Cons:
– Higher initial cost than Copper or standard Iridium plugs.

Best for: Drivers looking for the absolute longest service life and reliability, matching the manufacturer’s recommended service intervals for their 6.4 Hemi.

Expert Opinion: If you use your Hemi for long-distance cruising or work where maintenance downtime is costly, the extended life of Laser Platinum is invaluable. It’s truly the “set-it-and-forget-it” option.

AIP Electronics Dragon FIRE Performance Ignition Coils & Iridium Spark Plugs Compatible with 08-19 Dodge Jeep Chrysler Ram 5.7 5.9 6.1 6.4 V8 56029129AB UF504 LZFR5CI-11 92145 OEM Fit Kit-1565

This kit is unique because it offers a complete ignition system overhaul, pairing Iridium spark plugs with a full set of Dragon FIRE performance ignition coils. If your Hemi is aging, or if you’ve noticed misfires under load that plugs alone haven’t fixed, the coils might be failing. This kit provides up to 15% more energy than standard coils, maximizing the potential of the Iridium plugs and ensuring complete combustion across all cylinders.

Key features that stand out:
– Plugs & Coils Combo: A comprehensive solution for complete ignition renewal.
– Up to 15% More Energy: Delivers a stronger spark for improved throttle response and acceleration.
– Iridium Electrode Technology: Built for peak performance and longevity under load.

Pros:
– Excellent value proposition for replacing two critical components.
– Guarantees quicker cold starts and faster acceleration.
– High-grade, heat-resistant thermoplastics used in coil construction.

Cons:
– The overall cost is higher since you are buying a full set of coils as well as plugs.

Best for: Hemi owners needing a full ignition refresh who want maximum spark energy and improved overall power delivery.

Expert Opinion: Often, when plugs are worn, the coils aren’t far behind. Replacing both simultaneously eliminates guesswork and ensures the entire system is performing optimally. This is a powerful combination for rejuvenating an older 6.4 Hemi.

Comparison Insights: Choosing Your Hemi Spark Plug Material

When choosing the Best Spark Plugs For 6.4 Hemi, the material dictates cost, performance, and longevity. The 6.4L Hemi is unique in requiring 16 plugs, so the material choice has a major financial impact.

If you prioritize sheer spark intensity and responsiveness, the Champion Copper Plus plugs are fantastic due to copper’s high conductivity, but be prepared for replacements around every 15,000-20,000 miles. Copper is the most economical initial investment.

For the vast majority of drivers who want excellent performance combined with longevity, NGK Iridium IX (Products 1, 2, and 3) strikes the sweet spot. Iridium is tougher than Platinum, resists heat and wear incredibly well, and typically offers a service life of 60,000 to 80,000 miles. This is arguably the best everyday choice for the 6.4 Hemi.

If maintenance convenience is your chief concern and you want the absolute longest interval, the NGK Laser Platinum plugs (Product 6) are the clear winner. They are the OE plug for a reason, designed specifically to reach that 96,000-mile mark with minimal degradation. Platinum is engineered for endurance.

Finally, if your engine is showing signs of an overall aging ignition system, opting for the AIP Electronics Dragon FIRE kit (Product 7) that includes both Iridium plugs and new coils is a smart, comprehensive investment that maximizes spark strength.

Final Verdict

Deciding on the Best Spark Plugs For 6.4 Hemi depends heavily on your driving style and tolerance for maintenance intervals.

The Longevity King: We highly recommend the NGK Laser Platinum Spark Plugs (Product 6) for their 96,000-mile lifespan and guaranteed OE quality. Install these, and you won’t worry about them for years.

The Performance Sweet Spot: The NGK Set of 16 Iridium IX Spark Plugs (Product 3) provides the ideal mix of superior performance, strong durability, and manageable cost, making it the top choice for most Hemi enthusiasts.

The Full System Refresh: If your 6.4L Hemi has high mileage, go with the AIP Electronics Dragon FIRE Performance Ignition Coils & Iridium Spark Plugs Kit (Product 7). It’s the ultimate way to restore factory-fresh ignition power and then some.

Frequently Asked Questions About the Best Spark Plugs For 6.4 Hemi

Q1: Why does the 6.4L Hemi require 16 spark plugs?

The 6.4L Hemi engine, like its 5.7L counterpart, uses a twin-spark ignition system. This means there are two spark plugs per cylinder, totaling 16 plugs for the V8 engine. This design helps improve combustion efficiency, reduce emissions, and boost torque and horsepower, especially at lower RPMs.

Q2: What is the correct spark plug gap setting for a 6.4 Hemi?

The exact gap specification can vary slightly depending on the model year and specific plug manufacturer, but generally, the 6.4 Hemi requires a gap setting between 0.040 and 0.044 inches. Even if a plug is “pre-gapped” (like the Autowxjq), always verify the setting against your vehicle’s manual before installation to ensure optimal performance and avoid misfires.

Q3: How often should I replace the spark plugs in my 6.4L Hemi?

The replacement interval depends entirely on the plug material:
* Copper Plugs: Every 15,000 – 30,000 miles.
* Iridium Plugs (NGK Iridium IX): Every 60,000 – 80,000 miles.
* Platinum Plugs (NGK Laser Platinum): Up to 96,000 miles, matching the OE recommended service interval.

Q4: Can I mix different types of spark plugs in my twin-spark Hemi?

No. Because the 6.4L Hemi relies on precision timing and consistent spark energy across both plugs in a cylinder, you should use 16 identical spark plugs from the same manufacturer and material type. Mixing materials or brands can lead to inconsistent firing, misfires, and potentially engine damage.

Q5: Will upgrading to Iridium spark plugs improve my Hemi’s fuel economy?

While upgrading to high-quality Iridium or Platinum plugs primarily restores lost efficiency, you may notice a slight improvement in fuel economy, especially if your old plugs were severely worn. A more efficient, complete combustion cycle means less wasted fuel. However, the most immediate benefits will be felt in smoother idle, quicker cold starts, and better throttle response.

Q6: Do I need to replace the ignition coils when changing my spark plugs?

You don’t have to replace the coils every time you change the plugs, but it’s often recommended as preventative maintenance, particularly if your 6.4 Hemi has over 100,000 miles. Ignition coils degrade over time. If you choose a kit like the AIP Electronics Dragon FIRE combo (Product 7), you ensure that your plugs are receiving maximum voltage for their lifespan, maximizing the performance of your Best Spark Plugs For 6.4 Hemi.