10 Best Spark Plugs For 392 Hemi Reviewed

When I decided to really optimize the performance of my 6.4L (392) Hemi, the first thing I focused on was finding the absolute best spark plugs for 392 Hemi. These high-performance engines demand precision ignition, and choosing the right plug is critical for horsepower and efficiency. I’ve put together this detailed guide reviewing 10 top options, so you can confidently pick the ideal spark plug upgrade for your powerful Hemi engine.

IMAGE	PRODUCT NAME	AMAZON LINK
	NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack)…	View on Amazon
	NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack)…	View on Amazon
	NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack)…	View on Amazon
	NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack)…	View on Amazon
	16 pc NGK Iridium IX Spark Plugs compatible with Ram…	View on Amazon
	Set of 16 NGK 93893 LFR6AIX Iridium Spark Plugs -…	View on Amazon
	16 pc NGK Iridium IX Spark Plugs compatible with Ram…	View on Amazon
	16 pc Champion Copper Plus Spark Plugs compatible with…	View on Amazon
	16 pc NGK Iridium IX Spark Plugs compatible with Dodge…	View on Amazon
	Autowxjq Iridium Spark Plug 16pcs Replace Chrysler Dodge…	View on Amazon

NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack) Compatible With DODGE CHALLENGER SRT8 2011-2014 6.4L/392

This NGK Laser Platinum plug is essentially the benchmark for anyone seeking OEM quality and longevity in their 6.4L Challenger. Designed specifically for the earlier 392 models, it features dual platinum contacts which significantly resist gap erosion, meaning you won’t have to worry about performance drops between service intervals. If durability and reliable factory performance are your main goals, this 8-pack (remember, you’ll need two sets for a full change) is an excellent choice.

Key features that stand out:
– Dual platinum contacts reduces gap erosion.
– Ensures great durability and long life.
– Original equipment manufacturer approved.
– Precision laser welded platinum center electrode.

Pros:
– Excellent longevity due to dual platinum design.
– OEM-approved fitment for reliable performance.
– Highly stable idle and consistent ignition.

Cons:
– Since it is sold in an 8-pack, you need to purchase two sets for a full 16-plug change on the 392 Hemi.

Best for: Stock or lightly modified 2011-2014 Challenger 392 owners prioritizing durability and OEM replacement intervals.

Expert Opinion: This plug is a true workhorse. While it might not offer the marginal performance bump of iridium under extreme heat, its structural integrity and longevity make it the go-to choice for reliable, long-term Hemi maintenance.

NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack) Compatible With DODGE CHARGER R/T SCAT PACK 2015-2015 6.4L/392

Just like the Challenger variant, this plug offers the robust performance required for the 6.4L V8 found in the Charger Scat Pack. Although the part number is identical, NGK specifies this fitment to assure owners of the later model year 392 Hemi engines that they are getting the correct OEM-approved plug. The focus here remains on exceptional lifespan and consistent sparking, ensuring your Scat Pack remains responsive and efficient.

Key features that stand out:
– Engine V8, Engine Size 6.4L/392, Engine Family Hemi Gen III.
– Dual platinum contacts for maximum durability.
– Original equipment manufacturer approved.
– Precision laser welded platinum center electrode.

Pros:
– Matches factory specifications perfectly for the 2015 Scat Pack.
– Highly resistant to fouling and gap degradation.
– Promotes smooth power delivery.

Cons:
– Requires two 8-packs to complete the full 16-plug replacement.

Best for: 2015 Charger R/T Scat Pack owners looking for reliable OEM-spec performance and long service life.

Expert Opinion: If your Charger is driven daily and you prefer less frequent maintenance, the durability inherent in this Laser Platinum design is a massive benefit. It’s engineered to meet the stringent demands of the high-output Hemi.

NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack) Compatible With DODGE CHARGER SRT 392 2015-2015

Another specific application of the highly durable NGK Laser Platinum plug, this set is tailored for the 2015 Charger SRT 392 model. While the plug technology is consistent across these variants—focused on dual platinum durability—the dedicated listing provides peace of mind regarding fitment for this specific performance variant. Reliability is key when you’re dealing with the power of an SRT, and this plug delivers factory-level confidence.

Key features that stand out:
– Hemi Gen III architecture compatible.
– Dual platinum contacts reduces gap erosion.
– Ensures great durability and long life.
– Original equipment manufacturer approved.

Pros:
– Confirmed OEM fitment for the SRT 392 model.
– Excellent cold start performance.
– Resists premature wear under high load.

Cons:
– Performance enthusiasts seeking the absolute highest spark energy might lean toward specialized iridium plugs.

Best for: Owners of the 2015 Charger SRT 392 seeking exact factory replacement specifications.

Expert Opinion: For the majority of stock 392 Hemi drivers, these platinum plugs offer the best balance of initial cost, longevity, and reliable ignition performance. You can install them and forget about them for a long time.

NGK Laser Platinum Spark Plug LZTR6AP11EG (8 Pack) Compatible With JEEP GRAND CHEROKEE SRT 2014-2015 6.4L/392

The 6.4L 392 Hemi isn’t just found in muscle cars; it powers performance SUVs too, like the Grand Cherokee SRT. This NGK 8-pack ensures that the mighty Jeep has the same dependable, long-life ignition as its sedan and coupe counterparts. Given the added weight and potential for towing or spirited driving this SUV faces, the robust nature of the dual platinum construction is highly beneficial.

Key features that stand out:
– Specific fitment for the 6.4L/392 Grand Cherokee SRT.
– Dual platinum contacts reduces gap erosion.
– Ensures great durability and long life.
– Precision laser welded platinum center electrode.

Pros:
– Tested and approved for the SUV’s demanding operating conditions.
– Exceptional anti-fouling capabilities.
– Maintains accurate gap over thousands of miles.

Cons:
– Requires purchasing two separate kits for a full replacement.

Best for: Jeep Grand Cherokee SRT owners looking for OEM durability and peace of mind.

Expert Opinion: The consistency across these NGK Laser Platinum LZTR6AP11EG plugs is impressive. It highlights NGK’s commitment to providing an OE-quality replacement that sustains the high compression and operating temperature of the 6.4L Hemi across various platforms.

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

While specifically listed for the 5.7L Hemi V8 in the Ram 1500, these NGK Iridium IX plugs are often considered a significant performance upgrade across the entire Hemi family, including modified 392s. The Iridium IX line is known for its superior ignitability and sharper spark focus, which translates directly into better throttle response and reduced misfires, even under aggressive driving conditions. This is a full 16-plug kit.

Key features that stand out:
– IMPROVE IGNITION AND SPARK EFFICIENCY: Advanced electrodes produce complete and efficient combustion.
– REDUCE EMISSIONS AND MISFIRES: Promotes sharper spark focus.
– Full 16-piece kit.

Pros:
– Significantly improved throttle response compared to standard copper or platinum plugs.
– High durability due to iridium construction.
– Comes as a complete 16-piece set, simplifying the buying process.

Cons:
– The heat range might be slightly different than the stock 6.4L plug, requiring verification for non-5.7L applications.

Best for: 5.7L Ram owners, or 392 owners looking for a proven high-performance iridium upgrade (consulting heat range specifications required).

Expert Opinion: Iridium is the top tier for performance spark plugs because it can handle more heat and provide a finer, more reliable spark kernel. For owners who track their Hemi or simply demand the best response, Iridium IX is hard to beat.

Set of 16 NGK 93893 LFR6AIX Iridium Spark Plugs – 2015+ Hellcat Hemi 6.2L Dodge

This set is explicitly designed for the supercharged Hellcat 6.2L Hemi, but it is critically important for high-horsepower, forced-induction 392 Hemi builds. The “6” in LFR6AIX signifies a colder heat range than stock 392 plugs. If you’ve added a supercharger or turbo to your 392, a colder plug is essential to prevent pre-ignition and engine damage. This plug is factory pre-gapped for the Hellcat, but users must verify the gap for their specific boosted 392 setup.

Key features that stand out:
– Colder Heat Range (6), perfect for today’s high-tech, high-performance engines.
– Iridium IX material for high ignitability.
– Full set of 16 plugs included.
– Factory Pre-gapped to .031″.

Pros:
– Essential for modified, forced-induction 392 Hemi engines (running boost).
– Excellent performance under extreme pressure and temperature.
– Cold-rolled threads prevent cross-threading.

Cons:
– Too cold for a stock, naturally aspirated 392 Hemi, potentially leading to fouling.

Best for: Heavily modified or supercharged 6.4L (392) Hemi owners who require a colder heat range plug for safety and performance.

Expert Opinion: Never put a plug designed for a boosted engine in a stock naturally aspirated engine, and vice versa. This NGK LFR6AIX is a highly specialized plug—if you’re running 700+ horsepower on your 392, this is likely what you need.

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

Specifically covering the heavy-duty truck applications of both the 5.7L and 6.4L Hemi V8, this 16-pack of NGK Iridium IX plugs ensures rugged reliability. For 6.4L Hemi owners who use their trucks for heavy towing or frequent hauling, this plug offers the durability of iridium combined with a robust design suitable for sustained high-load operations. This is a direct replacement, full kit solution.

Key features that stand out:
– Compatible with both 5.7L and 6.4L V8 Ram 2500.
– Genuine NGK Parts ensuring quality fitment.
– Full 16-pack included.

Pros:
– Designed to withstand the added stress of heavy-duty truck use.
– Direct replacement fitment.
– Excellent overall ignition stability across the engine’s power band.

Cons:
– Truck-specific design might not be the primary choice for track-focused car owners.

Best for: Ram 2500 owners with the 6.4L Hemi who need a full 16-plug iridium upgrade prioritizing longevity under load.

Expert Opinion: Iridium is particularly beneficial in truck applications where the engine experiences long periods of heavy throttle input, as it drastically reduces the chance of gap blow-out and misfire compared to copper or older platinum designs.

16 pc Champion Copper Plus Spark Plugs compatible with Ram 1500 5.7L V8 2011-2024 HEMI V8 truck

Champion Copper Plus plugs represent the classic, tried-and-true ignition solution. While copper doesn’t have the lifespan of iridium or platinum, it is an outstanding conductor of heat and electricity, making it a favorite for racers and those who prefer frequent, low-cost maintenance. This 16-piece kit is primarily listed for the 5.7L Hemi but serves as an excellent budget or short-interval performance option for the 392 Hemi as well.

Key features that stand out:
– TRUST IN CHAMPION: Decades of racing heritage means proven reliability.
– Copper core provides maximum conductivity.
– Full 16-piece set included.

Pros:
– Best spark conductivity for crisp ignition performance.
– Highly affordable solution for frequent changes.
– Trusted brand in OE manufacturing.

Cons:
– Copper plugs have a significantly shorter lifespan than platinum or iridium, requiring replacement every 15,000–30,000 miles.

Best for: Budget-conscious owners, or those who frequently tune/race their Hemi and prefer the superior conductivity of copper with routine short-interval replacements.

Expert Opinion: If you’re pushing the limits and changing plugs every few oil changes for optimal performance, copper is often superior. However, for the average driver who wants 80k-100k miles out of a plug, this isn’t the choice.

16 pc NGK Iridium IX Spark Plugs compatible with Dodge Challenger 5.7L V8 2009-2020

Though targeted at the 5.7L Challenger, this full 16-pack of NGK Iridium IX plugs is a highly popular choice for naturally aspirated (NA) 392 owners looking for a direct iridium upgrade without changing the stock heat range. Iridium technology offers a finer wire center electrode, concentrating the spark energy for faster, more reliable combustion compared to thicker platinum electrodes.

Key features that stand out:
– High ignitability iridium construction.
– Full 16-pack simplifies ordering.
– Direct replacement auto parts.

Pros:
– Boosts overall engine responsiveness.
– Excellent longevity (typically 70,000+ miles).
– Proven NGK quality and reliability.

Cons:
– Slightly higher cost compared to the platinum options.

Best for: 392 Hemi owners looking for a premium, long-life, performance-oriented iridium plug upgrade for their Challenger or Charger (must verify correct heat range for the 6.4L).

Expert Opinion: This particular Iridium IX plug often hits the sweet spot for the NA performance enthusiast. You get the longevity of a premium material combined with the ignition benefits of a fine-wire tip.

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

This 16-piece kit offers an attractive alternative to the major brands, boasting iridium construction compatible with the entire Hemi V8 line, including the 6.4L. The main draw here is the combination of Iridium design and competitive pricing, offering high durability and excellent heat resistance, which is perfect for today’s high-performance engines. It’s a convenient, pre-gapped, full replacement set.

Key features that stand out:
– Iridium Design: Extremely high melting point for durability.
– Pre-gapped, allowing for direct installation.
– 2-year warranty and free replacement.

Pros:
– Very cost-effective iridium option.
– Full 16-piece set included.
– Strong warranty backing.

Cons:
– Not a major OEM supplier like NGK or Champion, requiring careful verification of performance consistency.

Best for: Hemi owners seeking the long-life benefits of Iridium technology at a more affordable price point.

Expert Opinion: While the specs look great (iridium core, 5000 ohms resistance), always approach non-OEM brands with caution, especially in highly sensitive performance engines like the 392 Hemi. However, for general use and daily driving, the iridium design should still provide excellent lifespan.

Comparison Short Insights

When choosing the best spark plugs for 392 Hemi, the biggest decision often boils down to material and application.

For stock or mildly tuned 6.4L engines, the NGK Laser Platinum (LZTR6AP11EG) variants stand out as the definitive OEM replacement. They are engineered for extremely long life, often rated for 80,000 to 100,000 miles, making them ideal for daily drivers who prioritize low maintenance. However, remember these are typically sold in 8-packs, meaning you must purchase two packs for a complete 16-plug Hemi swap.

If you are looking for a performance boost in a naturally aspirated 392, moving to the NGK Iridium IX series (like the 16 pc sets for the 5.7L/6.4L applications) provides a finer, sharper spark for better throttle response. Iridium offers a great compromise, delivering near-copper conductivity but with lifespan approaching that of platinum. These come in convenient 16-packs, covering the whole engine in one purchase.

Finally, for highly modified or forced-induction 392 Hemi builds, the colder heat range plugs, such as the NGK Hellcat Iridium (LFR6AIX), are non-negotiable. Using a standard heat range plug in a boosted motor can lead to catastrophic pre-ignition. Always verify the required plug heat range and gap based on your specific boost level and tune.

The Final Verdict

Choosing the right plug for your 392 Hemi depends entirely on your usage and modifications.

For the Daily Driver & Longevity: Go with the NGK Laser Platinum LZTR6AP11EG. These plugs are the gold standard for OEM reliability, offering maximum durability and minimizing the time spent wrenching on your engine. You simply cannot beat the reliability and long-term cost efficiency of this factory-approved platinum setup.

For Performance and Responsiveness (Naturally Aspirated): The NGK Iridium IX 16 pc sets are the winner. Iridium provides a superior, concentrated spark that most owners notice immediately in terms of crisper acceleration and smoother high-RPM operation, all while maintaining excellent lifespan.

For the Hardcore Tuner (Boosted 392): You must select a colder plug, making the NGK 93893 LFR6AIX Iridium (Hellcat spec) the only safe choice listed here. Its heat range is engineered to dissipate heat quickly, protecting your expensive modified engine from detonation.

Best Spark Plugs For 392 Hemi: FAQ

Do 392 Hemi engines use 8 or 16 spark plugs?

The 6.4L (392) Hemi engine uses 16 spark plugs, with two plugs per cylinder. This dual-plug setup is necessary for complete and efficient combustion in the large Hemi combustion chambers, which is why when buying sets, you usually need a quantity of 16 plugs for a complete change.

What is the ideal spark plug gap for a stock 6.4L Hemi?

For a stock, naturally aspirated 392 Hemi, the recommended spark plug gap is generally between 0.040 and 0.043 inches (1.0 to 1.1 mm), though this can vary slightly by plug type and model year. Always check the specific recommendation for your vehicle year or the specifications listed by the manufacturer of the spark plug you install.

Should I choose Platinum or Iridium spark plugs for my 392?

If you prioritize longevity and service interval, Platinum is excellent, often lasting up to 100,000 miles. If you seek optimal performance and throttle response, Iridium is generally preferred. Iridium features a finer tip for a hotter, more concentrated spark, making it the preferred upgrade for performance enthusiasts who want a long-life material.

When should I change the spark plugs in my 392 Hemi?

The OEM recommendation for the Laser Platinum plugs commonly used in the 6.4L Hemi is typically every 60,000 to 100,000 miles. If you use Copper plugs, replacement should occur much sooner, often every 15,000 to 30,000 miles. For highly modified engines, many tuners recommend checking and replacing spark plugs more frequently, regardless of material.

Do I need a colder plug if I tune my 6.4L Hemi?

Yes, if you significantly increase horsepower through forced induction (supercharger or turbocharger), or if you run a very aggressive tune, you absolutely need to switch to a colder heat range spark plug. Colder plugs transfer heat away from the tip faster, preventing the plug tip from becoming a hot spot that could cause pre-ignition and severely damage the engine.

Can I use the 5.7L Hemi spark plugs in my 6.4L 392 Hemi?

While the physical dimensions are often similar, the heat range specification can be different. Always verify that the heat range of the spark plug is appropriate for the higher compression and power output of the 6.4L Hemi engine. Using a plug that is too hot can lead to performance issues or engine damage.