7 Best Spark Plugs For L98 Engine Comparison Review

When I first started modifying my L98-powered vehicle, I quickly realized that ignition performance is key to consistent power, especially under load. We often overlook the simplest component—the spark plug—but installing the wrong set can severely hamper power and fuel efficiency. I’ve personally experimented with countless combinations to find the best spark plugs for l98 engine performance and longevity. This comprehensive guide breaks down seven leading options, helping you pick the right fit whether you’re building a reliable cruiser or a dedicated performance machine.

IMAGE	PRODUCT NAME	AMAZON LINK
	8 Pcs Iridium Spark Plugs Replace OEM# 41-110 41-162…	View on Amazon
	ACDelco 41-962 Professional Platinum Spark Plug, (8)	View on Amazon
	3Pcs L7T Spark Plugs for 36cc 43cc 47cc 49cc 52cc…	View on Amazon
	NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 PCSNEW	View on Amazon
	8 pc NGK V-Power Spark Plugs compatible with Chevrolet…	View on Amazon
	NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8…	View on Amazon
	BOSCH 9614 OE Fine Wire Double Iridium Spark Plug -…	View on Amazon

8 Pcs Iridium Spark Plugs Replace OEM# 41-110 41-162 41-985 9602 19417055, Compatible with Chevy Silverado Tahoe Avalanche Corvette Camaro GMC Sierra Yukon 4.8L 5.3L 5.7L 6.0L 6.2L 6.6L 8.1L V8

If you’re looking for a highly reliable, wide-compatibility set that meets or exceeds OEM specifications, these iridium replacements are an excellent choice for your L98. The iridium tip ensures a long service life and a consistently strong, stable spark, which is crucial for maximizing combustion efficiency in the LS platform. They arrive pre-gapped at the optimal setting for most stock applications, making installation straightforward right out of the box.

Key features that stand out:
– Broad Compatibility: Designed to replace numerous common OEM part numbers (41-110, 41-162, etc.) for a vast range of GM V8s.
– Pre-Gapped: Features a 0.04″ (1mm) pre-gap, ensuring reliable and consistent ignition performance immediately upon installation.
– Iridium Construction: Provides superior durability and resistance to heat and wear compared to standard platinum.

Pros:
– Excellent lifespan due to iridium construction
– Great value for a full set of 8
– Reliable spark delivery across the RPM range

Cons:
– Brand identity might not be as recognized as traditional OEMs.

Best for: Drivers seeking reliable, long-term performance without the premium cost of branded OEM iridium plugs.

Expert Opinion: For most stock or lightly modified L98 engines, iridium is the way to go for the best balance of performance and maintenance intervals. These plugs offer high-quality construction at an accessible price point.

ACDelco 41-962 Professional Platinum Spark Plug, (8)

ACDelco is often the go-to brand for GM enthusiasts, and their Professional Platinum series is a trusted standard. These plugs feature a double platinum point pad on both the center and ground electrodes, offering exceptional durability and consistent voltage demands. The pure copper core helps regulate the temperature, maximizing durability and effectively resisting fouling, making them a fantastic replacement if you want factory-level performance and reliability.

Key features that stand out:
– Double Platinum: Pads on both electrodes provide excellent durability and reduce wear on the ignition system.
– Fired-in Suppressor Seal: A three-glass type seal creates a gas-tight seal, which helps reduce radio frequency interference (RFI) and protects against compression loss.
– Pure Copper Core: This core design helps maintain a cooler electrode temperature for extended life and better fouling resistance.

Pros:
– Genuine GM/ACDelco quality ensures factory fit and performance
– Highly durable double platinum design
– Excellent resistance to RFI and fouling

Cons:
– Platinum doesn’t last as long as iridium under extreme heat conditions.

Best for: L98 owners prioritizing strict OEM compliance and guaranteed fitment for standard daily driving.

Expert Opinion: These are the reliable benchmark. While iridium plugs are technically superior in longevity, the ACDelco Professional series offers proven, consistent performance that the L98 engine was designed around.

3Pcs L7T Spark Plugs for 36cc 43cc 47cc 49cc 52cc 2-Stroke Small Engine Chainsaw Trimmer Mower Blower Brushcutter Replace NGK BPMR7A BPM7A Champion RCJ6Y RCJ7Y Spark Plug

IMPORTANT NOTE: While this is a high-quality replacement spark plug, the L7T is specifically designed for small, 2-stroke engines (like chainsaws, trimmers, or 49cc pocket bikes). This product is not compatible with the 4-stroke L98 V8 engine.

If you happen to be shopping for small engine components alongside parts for your L98, this is an excellent option for those specific applications. It provides high performance and replaces many common small engine plug numbers. However, installing it in the L98 would be impossible due to wildly different dimensions.

Key features that stand out (for small engines only):
– Specific Dimensions: Thread Diameter: 0.55in/14mm, designed for miniaturized powersports products.
– Broad Replacement: Directly replaces common small engine plugs like NGK BPMR7A and Champion RCJ6Y.

Pros:
– Excellent quality replacement for small 2-stroke engines
– Highly economical pack of three

Cons:
– Will not fit any L98, LS, or other GM V8 application.

Best for: Readers looking for replacement plugs for their small 2-stroke gardening equipment or mini-bike—not for their L98 engine.

Expert Opinion: We included this product only to clearly state that specialized plugs must be avoided when searching for the best spark plugs for l98 engine performance. Always ensure the plug is designated for the correct vehicle application (Chevy/GM V8).

NGK 6619 Iridium Spark Plugs LFR6AIX-11-6 PCSNEW

NGK’s Iridium IX line is famous among tuners and enthusiasts for its ability to handle demanding applications. These plugs are designed with a fine-wire iridium tip, allowing them to operate over a much wider heat range than conventional plugs. If you’ve made some light modifications (like a cold air intake or a tune) to your L98, the improved resistance to both carbon buildup and pre-ignition offered by the Iridium IX plug will keep your engine running smoothly.

Key features that stand out:
– Iridium IX Technology: Fine wire tip requires less voltage to fire, improving ignitability and fuel combustion.
– Wide Heat Range: Specifically designed to resist pre-ignition under higher cylinder pressures.
– Patented Triple Gasket: Ensures an absolute seal against combustion gas leakage, maintaining full cylinder pressure.

Pros:
– Top-tier performance plug choice
– Excellent durability and resistance to fouling
– Improved throttle response in some tuned engines

Cons:
– Sold in packs of 6, requiring two sets to complete the L98 V8.

Best for: Enthusiasts running mild tunes or seeking high performance and longevity from their L98 ignition system.

Expert Opinion: NGK Iridium IX plugs are often considered the gold standard for performance LS-series engines, offering proven reliability when pushed hard. They are a worthwhile investment for anyone serious about extracting maximum power.

8 pc NGK V-Power Spark Plugs compatible with Chevrolet Tahoe 4.8L 5.3L 5.7L 6.0L 6.2L V8 1998-2014

For owners of older or high-mileage L98 engines who prioritize economy and reliable function without needing extreme longevity, the NGK V-Power plugs are an exceptional budget option. These nickel plugs utilize an advanced V-groove design, which concentrates the spark near the center of the electrode, enhancing spark development and improving ignitability. They also feature a Trivalent Metal Plating, which is excellent at preventing corrosion and seizing in the cylinder head.

Key features that stand out:
– V-Groove Design: Provides a focused and stable spark, especially important in standard ignition systems.
– Trivalent Metal Plating: Offers superior anti-corrosion and anti-seizing properties, making future plug changes easier.
– Economical Performance: A tried-and-true design that offers reliable performance without the cost of precious metals.

Pros:
– Very affordable and come in a complete set of 8
– Reduces the chance of plugs seizing in aluminum heads
– Excellent standard performance for stock engines

Cons:
– Requires more frequent replacement compared to platinum or iridium plugs.

Best for: Budget-conscious maintenance, older vehicles, or stock L98 engines where frequent replacement is acceptable.

Expert Opinion: Don’t underestimate the power of the simple copper plug, especially the V-Power design. While they don’t last 100,000 miles, they deliver a very strong, stable spark—often preferred by racers who change plugs frequently.

NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8 PCSNEW

The NGK G-Power series bridges the gap between the budget V-Power and the premium Iridium IX lines. These plugs utilize a fine-wire platinum tip, which significantly increases durability and provides a much more consistent spark compared to standard nickel plugs. Like the Iridium line, the G-Power plugs are designed to operate over a wide heat range, resisting both carbon buildup and pre-ignition, making them a solid step up for reliable, mid-range performance tuning.

Key features that stand out:
– G-Power Platinum: Fine-wire platinum construction offers enhanced durability over standard copper plugs.
– Triple Gasket Seal: Patented process ensures maximum protection against gas leakage.
– Resists Pre-Ignition: Designed to handle moderate temperature demands without issue.

Pros:
– Improved longevity over copper/nickel plugs
– Excellent ignition consistency
– Strong resistance to fouling and heat

Cons:
– Longevity is slightly less than double platinum or iridium options.

Best for: Daily driven L98s where the owner wants extended life over copper but doesn’t require the extreme longevity of iridium.

Expert Opinion: TR5GP is a well-known heat range for many LS engines, making this a safe, high-quality, mid-tier upgrade. The platinum tip offers a great service life without the price jump of the Iridium IX line.

BOSCH 9614 OE Fine Wire Double Iridium Spark Plug – Pack of 4

Bosch brings serious technology to the table with their Double Iridium series, featuring iridium on both the firing pin and the ground electrode inlay. This design provides 4X longer life compared to copper plugs and dramatically enhances ignitability by reducing the required voltage by up to 24%. Crucially, these plugs feature nickel-plated rolled threads, which resist corrosion and eliminate the need for anti-seize compound, speeding up your installation process.

Key features that stand out:
– Double Iridium Design: Provides maximum performance and 4X longer life than copper plugs.
– 360-degree Laser Welded: Ultra-fine wire pin provides better ignitability and enhanced durability.
– Nickel-Plated Threads: Offers superior corrosion resistance and eliminates the messy requirement for anti-seize.

Pros:
– Market-leading lifespan and durability
– Highly efficient spark reduces strain on the coil packs
– Simplifies installation (no anti-seize needed)

Cons:
– Sold in packs of four, necessitating two packs for a full L98 installation.

Best for: L98 owners prioritizing maximum lifespan, cutting-edge technology, and efficiency, especially in higher-mileage engines.

Expert Opinion: The Bosch Double Iridium is a top contender for the longest-lasting plug available. Reducing the required voltage is a fantastic benefit for preserving your ignition coils over the life of the engine.

Comparison Insights: Which Plug Material is Best for Your L98?

When reviewing the best spark plugs for l98 engine applications, the decision often comes down to the material: Copper/Nickel, Platinum, or Iridium.

For Budget and Basic Performance, the NGK V-Power (Nickel/Copper core) is your choice. It delivers a sharp, strong spark but must be changed much more frequently (every 30k miles or less). These are excellent if you plan to do frequent performance tuning where changing plugs is routine.

If you are looking for Excellent OEM Reliability and Durability, the ACDelco Platinum and NGK G-Power Platinum are the sweet spots. Platinum plugs typically last around 60,000 to 80,000 miles and handle the standard heat range of the L98 very well.

For the Absolute Longest Life and Performance, Iridium wins hands down. Plugs like the Bosch Double Iridium and the NGK 6619 Iridium are designed to go 100,000 miles or more and maintain spark integrity better under high boost or high cylinder pressure. They cost more upfront but save significantly on replacement costs and labor over time.

If your L98 is supercharged or heavily modified, a colder heat range (usually one step colder than stock) is crucial. Always check with your tuner to ensure your selected material and heat range are appropriate for the power level.

Final Verdict: Choosing the Right Spark Plug for Your L98

Finding the best spark plugs for l98 engine requires matching your driving habits and budget to the plug technology.

The Top Tier: For Maximum Longevity and Efficiency
If you want to install a plug and forget about it for the next 100,000 miles while maximizing coil life, the BOSCH 9614 OE Fine Wire Double Iridium is the ultimate choice. The double iridium design is unparalleled in terms of lifespan and efficiency.

The Performance Pick: For Enthusiasts and Tuned Engines
For L98 owners who have performance mods and want exceptional spark consistency under high demands, we recommend the NGK 6619 Iridium Spark Plugs. NGK is synonymous with LS engine performance tuning.

The Reliable OEM Standard: The Best Value Replacement
For stock engines prioritizing guaranteed fitment and ACDelco quality at a reasonable price, the ACDelco 41-962 Professional Platinum Spark Plug remains the highly reliable, common-sense choice.

Best Spark Plugs For L98 Engine FAQ

What is the correct spark plug gap for a stock L98 engine?

For a stock L98 (which is part of the LS family), the typical factory recommended spark plug gap is 0.040 inches (1.0 mm). However, if your L98 is turbocharged, supercharged, or running a very high compression ratio, tuners often recommend closing the gap slightly (e.g., to 0.030–0.035 inches) to prevent spark blow-out under extreme cylinder pressure. Always check the plug’s factory gap and adjust if necessary for your specific application.

Should I choose platinum or iridium spark plugs for my L98?

The choice depends on priority. Platinum plugs (like the ACDelco 41-962) offer great durability and are a reliable, cost-effective replacement for standard driving, lasting 60k-80k miles. Iridium plugs (like the NGK 6619 or Bosch 9614) are the current performance leaders, offering an extremely fine tip for better ignitability and longevity of 100k+ miles. For general, low-maintenance use, iridium is often considered the best spark plugs for l98 engine operation.

Do I need to use anti-seize compound when installing new L98 spark plugs?

It depends on the plug material. Older copper plugs required anti-seize. However, most modern platinum and iridium plugs, especially those from Bosch and NGK, come with a trivalent or nickel plating specifically designed to resist corrosion and seizing in aluminum heads. Applying anti-seize to pre-coated threads can actually cause you to overtighten the plug, potentially stripping the threads or damaging the plug gasket. Unless the manufacturer explicitly recommends it, avoid using anti-seize on modern, plated plugs.

How does the heat range affect L98 engine performance?

The heat range determines how quickly the plug can transfer heat away from the firing tip to the cylinder head. A hotter plug is better for preventing fouling in stock, low-stress motors. A colder plug (like the TR6 often used in forced induction applications) transfers heat faster, which is essential for modified L98 engines that generate much higher cylinder temperatures. Using too hot a plug in a high-performance L98 can cause pre-ignition and engine damage.

How often should I change the best spark plugs for l98 engine performance?

Maintenance intervals depend on the plug material and driving conditions:
* Copper/Nickel (V-Power): Every 30,000 miles.
* Platinum (ACDelco/G-Power): Every 60,000 to 80,000 miles.
* Iridium (NGK/Bosch): Every 100,000 miles or more.
For heavily modified or race L98 engines, plugs should be checked and replaced much more frequently, potentially as often as every 10,000 to 20,000 miles.

Are specialized “indexing” procedures necessary for L98 plugs?

Spark plug indexing is the practice of positioning the ground electrode facing away from the incoming air/fuel charge to maximize combustion. While some performance builders argue for indexing, it is generally not necessary for street-driven or mildly modified L98 engines. Modern engine designs and high-quality iridium plugs negate most of the minor theoretical benefits indexing provides. Focus more on using the correct heat range and gap size.