We researched and compared the top spark plugs for the 5.7L Hemi engine found in Ram, Dodge Charger, Challenger, and Jeep Grand Cherokee. Our evaluation is based on manufacturer specifications, published industry standards, and aggregated owner feedback from forums and review sites. We considered factors like electrode material, heat range, gap retention, and reported longevity to help you choose the best plug for your driving needs.
| Photo | Product | Score | Buy |
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NGK (93220) LFR6AIX-11 Iridium IX Best Overall Iridium tip, 0.044 in. gap, heat range 6 |
9.2 | 🛒 Check Price |
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Denso (4713) Iridium TT Best Premium Twin-tip iridium, 0.044 in. gap, heat range 6 |
8.9 | 🛒 Check Price |
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Champion (9409) Copper Plus Best Budget Copper core, 0.035 in. gap, heat range 6 |
8.1 | 🛒 Check Price |
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E3 (E3.54) DiamondFIRE Best for Performance Diamond-shaped ground electrode, 0.055 in. gap, heat range 6 |
8.4 | 🛒 Check Price |
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ACDelco (41-962) Iridium Best OEM Replacement Iridium tip, 0.040 in. gap, heat range 6 |
8.7 | 🛒 Check Price |
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Bosch (4417) Platinum+4 Best Multi-Electrode Four ground electrodes, platinum center, 0.044 in. gap |
7.8 | 🛒 Check Price |
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Autolite (XP985) Iridium XP Best Value Iridium Iridium tip, 0.044 in. gap, heat range 6 |
8.2 | 🛒 Check Price |
1. NGK (93220) LFR6AIX-11 Iridium IX: Best Overall
In our research, the NGK Iridium IX stands out as the most recommended plug for stock to mildly tuned 5.7 Hemi engines. It uses a fine iridium tip that requires less voltage to fire, improving combustion efficiency and throttle response. Owner feedback consistently reports smooth idle and improved fuel economy over standard copper plugs. The pre-gapped design saves installation time, though we advise verifying the gap before installation.
However, this plug is not ideal for forced induction or nitrous applications where a colder heat range is needed. Some owners with heavy towing or sustained high-load driving have reported shorter life than expected. If you have a heavily modified Hemi, consider a colder plug like the NGK LFR7AIX.
- Iridium center electrode for long service life and consistent spark
- Pre-gapped to 0.044 inches for easy installation
- OE replacement for many 5.7 Hemi applications
Pros: Excellent performance and throttle response; Long lifespan reported by many owners
Cons: Not designed for high-boost or heavily modified engines
2. Denso (4713) Iridium TT: Best Premium
The Denso Iridium TT is a premium option that uses both an iridium center electrode and a platinum ground electrode. This combination is designed to resist gap erosion much longer than standard iridium plugs. In our evaluation of owner feedback, many report these plugs lasting well beyond the typical change interval, making them a good choice for those who want a fit-and-forget solution. The twin-tip design also provides a focused spark for efficient combustion.
However, the higher cost may not be justified for drivers who change plugs frequently or have a stock engine. Some owners have noted that the performance gain over a standard NGK Iridium IX is marginal. If you are on a tight budget, you may prefer a more affordable option.
- Twin-tip iridium design for extended durability
- Platinum ground electrode reduces gap wear
- OE for many Toyota and Lexus, but fits 5.7 Hemi
Pros: Extremely long service life up to 120,000 miles claimed; Consistent performance over entire life
Cons: More expensive than comparable iridium plugs
3. Champion (9409) Copper Plus: Best Budget
The Champion Copper Plus is the budget-friendly choice for 5.7 Hemi owners who don’t mind changing plugs more often. Copper plugs offer excellent conductivity and heat transfer, which can help prevent misfires in older engines. Owner feedback indicates they perform well for everyday driving and light towing. The price is significantly lower than iridium plugs, making them a practical option for those on a budget.
However, these plugs wear out faster typically around 30,000 miles and may require re-gapping. They are not suitable for high-performance or modified engines where a finer electrode is needed for reliable spark under boost. If you want a longer-lasting plug, consider an iridium option.
- Copper core for good conductivity and heat dissipation
- Very affordable price point
- Traditional design works well in stock engines
Pros: Low cost makes frequent replacement easy; Reliable performance for daily driving
Cons: Shorter lifespan than iridium or platinum plugs
4. E3 (E3.54) DiamondFIRE: Best for Performance
The E3 DiamondFIRE plug features a patented diamond-shaped ground electrode that exposes more of the spark to the air-fuel mixture, promoting a larger and more complete burn. In our research, some 5.7 Hemi owners report a slight increase in low-end torque and smoother acceleration. The plug is made with a nickel-plated shell for corrosion resistance. It is a popular choice for those seeking a performance edge without major modifications.
However, the recommended gap of 0.055 inches is wider than stock, and the plugs often arrive with inconsistent gaps. We recommend checking and adjusting the gap before installation. Some owners have experienced misfires if the gap is not set correctly. This plug may not be ideal for stock engines that require a tighter gap.
- Unique diamond ground electrode for larger flame kernel
- Nickel-plated shell resists corrosion
- Designed for improved fuel efficiency and power
Pros: Noticeable throttle response improvement per some owners; Unique design may reduce fouling
Cons: Gap must be carefully set; not pre-gapped accurately
5. ACDelco (41-962) Iridium: Best OEM Replacement
The ACDelco Iridium plug is a solid OEM-grade option for the 5.7 Hemi, particularly for those who prefer a brand known for GM vehicles. It features an iridium tip and a platinum ground pad for durability. Owner feedback indicates it works well in stock Rams and Chargers, providing smooth idle and reliable ignition. The plug is pre-gapped, but we still recommend verifying the gap as shipping can alter it.
That said, some owners have reported that these plugs do not perform as well as NGK or Denso in high-performance applications. The heat range may not be suitable for forced induction. If you have a stock engine and want a trusted brand, this is a good choice, but performance enthusiasts may want to look elsewhere.
- OE quality for GM vehicles, also fits many Hemi applications
- Iridium center electrode for long life
- Pre-gapped to specification
Pros: Consistent quality and reliable performance; Long service life comparable to NGK/Denso
Cons: May not be the best choice for heavily modified engines
6. Bosch (4417) Platinum+4: Best Multi-Electrode
The Bosch Platinum+4 uses four ground electrodes to provide multiple spark paths, theoretically improving combustion and extending plug life. In our research, some 5.7 Hemi owners report a smoother idle and better fuel economy. The platinum center electrode is durable. However, we found that feedback is highly mixed, with a significant number of owners experiencing misfires or no noticeable improvement over standard plugs.
This plug may not be the best fit for the Hemi’s cylinder head design, as the electrode arrangement can interfere with the flame kernel. Many forum users recommend sticking with a single-tip design. If you have a stock engine and want to try something different, it might work, but we advise caution. For most, a conventional iridium plug is a safer bet.
- Four ground electrodes for multiple spark paths
- Platinum center electrode resists wear
- Designed for smoother idle and longer life
Pros: Smooth idle reported by some owners; Unique design may extend plug life
Cons: Mixed reviews on performance; some report misfires
7. Autolite (XP985) Iridium XP: Best Value Iridium
The Autolite Iridium XP is a budget-friendly iridium plug that offers a good balance of performance and value. It features a fine-wire iridium tip and a platinum ground pad, similar to more expensive brands. Owner feedback generally positive, with many reporting improved throttle response and smooth operation. It is a suitable replacement for stock Hemi engines and offers longer life than copper plugs.
However, we found occasional complaints about inconsistent gap from the factory, so careful inspection is necessary. Some users have experienced premature fouling in certain driving conditions. This plug is a good choice for cost-conscious buyers who want iridium technology, but those seeking maximum durability may prefer NGK or Denso.
- Fine-wire iridium tip for low voltage requirement
- Platinum ground pad for extended life
- Affordable iridium option
Pros: Good performance for the price; Longer life than copper plugs
Cons: Some owners report quality control issues with gap
Frequently Asked Questions
What spark plug is recommended for a stock 5.7 Hemi?
For a stock 5.7 Hemi, NGK Iridium IX (93220) is the most commonly recommended plug. It offers reliable performance, long life, and is pre-gapped to the correct specification. Many owners also use Denso Iridium TT or ACDelco Iridium with good results.
How often should I change spark plugs on a 5.7 Hemi?
For iridium plugs, the recommended interval is typically 100,000 miles, but many owners change them earlier around 60,000-80,000 miles for optimal performance. Copper plugs should be changed every 30,000 miles. Always check your owner’s manual for the specific recommendation.
Can I use copper plugs in my 5.7 Hemi?
Yes, you can use copper plugs like the Champion Copper Plus. They are affordable and work well in stock engines. However, they have a shorter lifespan and may need to be changed more frequently. They are not recommended for modified or high-performance engines.
What gap should I set for 5.7 Hemi spark plugs?
The factory gap for most 5.7 Hemi engines is 0.044 inches. However, some aftermarket plugs may recommend a different gap. Always check the manufacturer’s specification and use a gap tool to verify. An incorrect gap can cause misfires and poor performance.
Are E3 spark plugs good for the 5.7 Hemi?
E3 DiamondFIRE plugs can provide a performance improvement for some owners, especially in throttle response. However, they require careful gapping and may not work well with all engine modifications. Many owners report positive results, but some have experienced misfires. We recommend them for enthusiasts willing to experiment.
Our Verdict
After researching and comparing the top spark plugs for the 5.7 Hemi, we recommend the NGK Iridium IX (93220) as the best overall choice for most owners due to its reliable performance, long life, and excellent owner feedback. For those seeking a premium option with the longest lifespan, the Denso Iridium TT is a strong runner-up. Budget-conscious buyers should consider the Champion Copper Plus, but be prepared for more frequent changes.
Last reviewed and spec-checked: June 21, 2026. We re-check our picks and listings periodically.
