Best Spark Plugs For 350 Small Block

I’ve spent years wrenching on classic Chevys, and if there’s one thing I’ve learned about the venerable 350 small block, it’s that the right ignition components are everything. Choosing the best spark plugs for 350 small block performance isn’t just about thread size; it’s about selecting the proper heat range and conductivity, especially if you’ve done modifications like adding headers or a hotter cam. We’re going to dive into proven copper core, V-power, and performance options to make sure your SBC is firing clean and strong every time you turn the key.

IMAGE	PRODUCT NAME	AMAZON LINK
	8 pc NGK 6630 V-Power Spark Plugs for 1052895W 15…	View on Amazon
	NGK Standard Series Spark Plug YR5 (8 Pack) for CHEVROLET…	View on Amazon
	ACCEL 8198 Performance U-Groove Header Spark Plug – Pack…	View on Amazon
	JDMSPEED New 10.5mm Spark Plug Wire Set Replacement for…	View on Amazon
	ACCEL 0576S-4 Shorty Copper Core Spark Plug, (Pack of 4)	View on Amazon
	NGK Standard Series Spark Plug BR6S (8 Pack) for…	View on Amazon
	NGK Standard Series Spark Plug BR6S (8 Pack) for…	View on Amazon
	ACDelco GM Original Equipment R45TS (19354415) Conventional…	View on Amazon
	NGK V Power Spark Plug UR4 (8 Pack) Compatible With…	View on Amazon
	Universal Spark Plug Wire Set – 8.5mm Red High…	View on Amazon

8 pc NGK 6630 V-Power Spark Plugs for 1052895W 15 16 1765179 18 1835800T 1835906T 18C2 18S 19 25 25BP 25C2 25DP2 25S 26 2R45TS 2R46TS 3851859 3851861 44TS 45TS 46TS 5020 5024 5025 5026 5213202S 577

The NGK 6630 V-Power plugs are a fantastic choice if you’re seeking reliability and efficient power delivery for a standard or lightly modified 350. NGK uses a unique V-groove design on the center electrode which directs the spark to the edges, resulting in a more consistent and focused ignition. These plugs offer excellent anti-fouling properties and are designed as a direct, trouble-free replacement for many original equipment plugs, ensuring easy installation and immediate performance improvement.

Key features that stand out:
– V-Groove Center Electrode: Improves ignition and reduces misfires.
– Genuine NGK Parts: Assurance of quality and fitment.
– Durable Construction: Built for longevity and consistent heat management.

Pros:
– Excellent reliability for daily drivers and cruisers.
– Designed to increase ignitability compared to standard plugs.
– Resist fouling well.

Cons:
– May not handle extreme high-boost applications compared to specialized Iridium.

Best for: Reliable stock replacement and mild street performance setups.

Expert Opinion: NGK V-Power plugs are a go-to standard for many mechanics working on small block Chevys. They provide a great blend of price, longevity, and noticeable throttle response without requiring complex tuning.

NGK Standard Series Spark Plug YR5 (8 Pack) for CHEVROLET CHEVELLE MALIBU 1972-1972 5.7L/350

Specifically packaged and indexed for the classic 1972 Chevelle/Malibu 5.7L, the NGK YR5 standard series plug is built for traditional performance. These feature a pure alumina silicate ceramic insulator, which is key for superior strength and efficient heat transfer away from the combustion chamber. The copper core aids significantly in heat removal, making this a reliable option for period-correct restorations or engines running at factory specifications.

Key features that stand out:
– Trivalent Metal Plating: Provides excellent anti-corrosion and anti-seizing properties.
– Copper Core: Maximizes heat transfer for durability.
– Triple Seals: Designed to prevent leakage of combustion gases.

Pros:
– Strong resistance to corrosion and seizing in the cylinder head.
– Specifically cataloged for vintage SBC applications.
– Excellent heat management characteristics.

Cons:
– Standard design offers conventional performance levels.

Best for: Period-correct restorations and stock 1970s 350 engines.

Expert Opinion: When dealing with older cast iron heads, you want plugs that won’t seize. The trivalent plating on these NGK plugs is a huge benefit for long-term maintenance and protection.

ACCEL 8198 Performance U-Groove Header Spark Plug – Pack of 8

If your 350 small block is sporting large headers, you know clearance can be a nightmare. The ACCEL 8198 plugs are designed with a shortened body profile, making them ideal for use in cramped spaces where header tubes might interfere with standard plugs. Beyond the physical benefit, the U-Groove electrode design enhances combustion, providing improved throttle response and promising better fuel economy under normal driving conditions.

Key features that stand out:
– U-Groove Design: Enhanced combustion efficiency.
– Shortened Plug Body: Essential for high-performance applications with headers.
– Improved Fuel Economy: Designed to reduce fouling and misfire.

Pros:
– Solves clearance issues common in performance SBC builds.
– Delivers a significantly hotter, more consistent spark.
– Provides better power at higher RPMs.

Cons:
– The shortened profile means they require specialized tools for removal in some cases.

Best for: Modified 350s with clearance issues due to aftermarket headers.

Expert Opinion: Clearance is often overlooked until installation day. These shorty plugs save a lot of headaches and still deliver the punch you expect from a dedicated performance plug.

JDMSPEED New 10.5mm Spark Plug Wire Set Replacement for HEI SBC BBC 350 383 454 Electronic

While not spark plugs themselves, quality wires are crucial for delivering the ignition charge. This JDMSPEED wire set provides heavy-duty 10.5mm wires, which is significantly thicker than stock, ensuring maximum energy transfer with minimal resistance. They are ready for install straight out of the box and are specifically designed for HEI (High Electronic Ignition) systems common on upgraded small blocks, handling the high voltage these distributors produce.

Key features that stand out:
– 10.5mm Racing Wires: Superior insulation and conductivity.
– HEI Compatibility: Built to handle the high voltage requirements of electronic ignition.
– Universal Fitment: Includes various lengths to accommodate routing in most SBC/BBC engine bays.

Pros:
– Dramatically reduces electrical resistance and crossfire.
– Ready to install with boots and terminals pre-fitted.
– Excellent value for a high-performance wire set.

Cons:
– The universal length requires careful routing and potentially trimming excess.

Best for: Upgrading the entire ignition system on a 350 running an HEI distributor.

Expert Opinion: If you upgrade to performance plugs but run old, cheap wires, you’re leaving power on the table. A thick wire set like this is essential to ensure the spark reaches the plug effectively, especially under load.

ACCEL 0576S-4 Shorty Copper Core Spark Plug, (Pack of 4)

Similar to the 8198 model, the ACCEL 0576S-4 plugs emphasize a compact, shortened design for tight engine bays, particularly those with restrictive manifolds or large diameter headers. Utilizing a traditional copper core, these plugs are excellent conductors of electricity and heat, offering instant throttle response and sustained power. Note that this package only includes four plugs, meaning you would need two sets to outfit a V8 engine.

Key features that stand out:
– Shorty Design: Essential for clearance issues in modified engines.
– Copper Core: Excellent conductivity for a strong, quick spark.
– Instant Throttle Response: Designed to reduce latency and misfires.

Pros:
– Highly effective for applications with minimal plug clearance.
– Copper core provides a hot spark that enthusiasts rely on.
– Durable construction handles high RPMs well.

Cons:
– Sold in a pack of four, requiring two purchases for a V8.

Best for: Performance 350s requiring short body plugs for extreme clearance needs.

Expert Opinion: Copper is still the king of conductivity. For a street/strip car, running a high-quality copper shorty plug provides reliable performance and the necessary physical fitment.

NGK Standard Series Spark Plug BR6S (8 Pack) for CHEVROLET C10 SUBURBAN 1969-1970 5.7L/350

The NGK BR6S plugs are designed as a factory-style replacement for specific vintage C10 and Suburban models equipped with the 5.7L 350. These standard series plugs boast NGK’s patented design elements, including the corrugated ribs to prevent flashover—where the spark travels up the outside of the insulator instead of firing at the tip. They provide consistent performance and reliable cold starts, making them an excellent maintenance choice.

Key features that stand out:
– Engine Family Specific: Perfect fitment for classic 350 small block Gen I engines.
– Corrugated Ribs: Prevents external flashover for reliable spark delivery.
– Pure Alumina Ceramic Insulator: Ensures effective heat transfer.

Pros:
– Highly durable and reliable for stock applications.
– Excellent resistance to electrical interference and misfires.
– Trivalent metal plating reduces the chance of seizing.

Cons:
– Best suited for stock heat ranges; not ideal for boosted applications.

Best for: Restoring or maintaining stock 1960s/1970s C10 trucks and Suburbans.

Expert Opinion: When working on these older workhorses, reliability is key. The NGK BR6S is a bulletproof plug that performs exactly as the manufacturer intended for factory performance.

NGK Standard Series Spark Plug BR6S (8 Pack) for CHEVROLET K10 PICKUP 1969-1970 5.7L/350

Identical in specification to the previously reviewed BR6S, this pack is specifically targeted toward the K10 Pickup crowd. The reliability of the NGK standard series makes them a top seller for vintage truck owners. They offer the necessary robustness and anti-seizing properties required for engines that might sit for extended periods or face varied driving conditions, from highway cruising to light off-roading.

Key features that stand out:
– Standard Heat Range: Optimized for factory compression and timing.
– Trivalent Metal Plating: Protects threads against seizing in aluminum or cast iron heads.
– Copper Core: Reliable and efficient heat dissipation.

Pros:
– Dependable performance across various temperatures.
– Excellent fitment guarantee for listed K10 models.
– Affordable and long-lasting maintenance option.

Cons:
– Not the highest performance plug available.

Best for: Reliable maintenance and general-purpose use in classic K10 pickups.

Expert Opinion: Don’t overthink it for a stock engine. These NGK standards are proven winners that provide consistent performance without demanding premium fuel or exotic ignition systems.

ACDelco GM Original Equipment R45TS (19354415) Conventional Spark Plug

If you want the factory feel and original equipment manufacturer (OEM) performance for your small block Chevy, the ACDelco R45TS is the way to go. These plugs are often cited as the classic, standard replacement for countless 350 applications. Featuring a copper core for heat transfer and a Black Onyx coating to resist corrosion, they are built specifically to GM specifications for guaranteed fit and function.

Key features that stand out:
– GM Original Equipment: Guaranteed fit and performance matching factory standards.
– Black Onyx Coating: Provides superior corrosion resistance.
– Ribbed Suppressor Seal: Prevents spark flashover and engine misfires.

Pros:
– The definitive OEM plug for many classic SBCs.
– Durable construction specifically formulated for GM engines.
– Excellent resistance to fouling and corrosion.

Cons:
– Copper core design requires replacement more frequently than platinum plugs.

Best for: Owners seeking strict factory restoration or reliable, budget-friendly performance.

Expert Opinion: The R45TS is the benchmark plug for the SBC. It’s what the engine was designed to run on, and if your engine is stock, this plug will provide the best balance of longevity and performance.

NGK V Power Spark Plug UR4 (8 Pack) Compatible With CHEVROLET K10 1976-1984 5.7L/350

Offering the popular V-Power technology in a slightly different heat range (UR4), this set is tailored for later model 350s found in K10 pickups from the mid-70s through the early 80s. The V-Power design delivers a consistent, powerful spark, helping to ensure cleaner combustion. Although these are non-shorty plugs, their standard dimensions offer good sealing and durability for general street use.

Key features that stand out:
– V-Power Design: Enhanced ignition performance and quick starts.
– Standard Resistor: Helps suppress radio frequency interference (RFI).
– Compatible with Later Gen I 350s: Specific heat range for these applications.

Pros:
– Improved cold starting compared to older designs.
– V-groove technology ensures reliable firing.
– Specific manufacturer heat range (4) for optimal performance in designated years.

Cons:
– Less applicable for early 350 builds requiring a hotter plug.

Best for: Later model (1976-1984) K10 pickups seeking an upgrade from basic conventional plugs.

Expert Opinion: V-Power is a great middle ground. It’s affordable like copper but offers an undeniable advantage in ignitability and resistance to fouling compared to basic standard plugs.

Universal Spark Plug Wire Set – 8.5mm Red High Performance – Compatible with Chevy GM SBC BBC Engines Small Block 305 307 327 350 Big Block 427 454 502 and More with HEI Distributor

If you’re refreshing your entire 350 small block ignition system, this universal 8.5mm wire set is a solid, high-performance choice. The spiral wound design coupled with heavy-duty silicone jackets provides outstanding resistance to heat and oil, common enemies in a hot engine bay. These wires are designed specifically for HEI distributors, ensuring maximum conductivity and spark energy reaches the plug tips.

Key features that stand out:
– 8.5mm Spiral Wound Design: Low resistance path for high-energy spark.
– High-Temperature Silicone Boots: Excellent protection against exhaust heat and abrasion.
– Universal HEI Fitment: Works across a wide range of SBC and BBC engines with electronic ignition.

Pros:
– Significantly upgrades spark delivery over old or stock wires.
– Highly durable materials resist wear and tear.
– 12-month warranty provides peace of mind.

Cons:
– Universal sets often require custom wire routing and potential trimming.

Best for: Budget-conscious builders needing a full, high-performance wire upgrade for their HEI-equipped 350.

Expert Opinion: The value proposition here is huge. You get excellent insulation and low resistance, which is vital for any performance SBC build that sees high RPMs or extended use.

Comparison Insights: Choosing the Right 350 Plug and Wires

When evaluating the best spark plugs for 350 small block engines, it really comes down to what you’re doing with the car.

For stock or lightly modified engines where reliability is the priority, NGK Standard Series plugs (like the YR5 or BR6S) or the ACDelco R45TS are the safest bet. The R45TS is the quintessential OEM choice, offering proven performance that the motor was originally designed for.

If you’re looking for a step up in performance without changing the heat range significantly, the NGK V-Power 6630 plugs offer superior ignitability due to their V-groove design, often resulting in slightly crisper throttle response and better cold starts than traditional plugs.

For high-performance 350s—especially those with large, aftermarket headers that create clearance issues—the ACCEL 8198 or 0576S-4 Shorty plugs are non-negotiable. Their specialized body profile prevents header tube interference while delivering a strong copper-core spark.

Finally, remember that plugs are only half the system. If you are running an HEI distributor, an investment in high-conductivity ignition wires, such as the 10.5mm JDMSPEED or the 8.5mm Universal set, is necessary to ensure the high-voltage spark actually makes it to the plug effectively. Thicker wires reduce energy loss, which is critical for performance applications.

Final Verdict: Our Top Picks by Category

Picking a single “best” plug is impossible for such a versatile engine, but we can recommend the top performers for common use cases:

For the Daily Driver/Cruiser (Best Value & Reliability):
We’d lean toward the ACDelco GM Original Equipment R45TS. You simply can’t beat the factory engineering for a stock motor; they just work.

For Modified Engines with Header Clearance Issues:
The ACCEL 8198 Performance U-Groove Header Spark Plugs are the clear winner here. They solve a persistent problem in high-performance builds while still offering excellent copper core conductivity.

For Performance Upgrade (Non-Clearance Issues):
The 8 pc NGK 6630 V-Power Spark Plugs offer the best performance-to-cost ratio. The V-power design provides consistent ignitability, making them excellent for street/strip applications where quick response matters.

Essential Ignition System Upgrade:
Don’t overlook the wires! The Universal Spark Plug Wire Set (8.5mm Red High Performance) is a critical, cost-effective upgrade to ensure maximum spark delivery from your HEI system.

Frequently Asked Questions About Best Spark Plugs For 350 Small Block

Q: What spark plug gap should I run on my 350 small block?

A: For a stock 350 small block using a conventional points distributor, the standard gap is typically 0.035 inches. If you’ve upgraded to an HEI (High Energy Ignition) system, which delivers a hotter spark, you can safely widen the gap to 0.045 inches. Always check your specific engine manual or plug manufacturer recommendations if you have heavy modifications like high compression or forced induction.

Q: Is it better to use copper or platinum spark plugs in a classic 350 engine?

A: Generally, copper core spark plugs are recommended for performance and conventional 350 small blocks. Copper is the best conductor, offering a strong, consistent spark necessary for good combustion. Platinum and iridium plugs are durable and last much longer, but for classic performance applications, the superior conductivity of copper is often preferred, even if it means changing the plugs more frequently.

Q: What does the “heat range” of a spark plug mean for my 350?

A: The heat range refers to the plug’s ability to dissipate heat from the combustion chamber. A colder plug (higher heat range number on NGK, lower on ACDelco) moves heat away faster and is needed for high-performance, high-RPM, or boosted 350s to prevent pre-ignition. A hotter plug is better for stock engines that run cooler and helps burn off carbon deposits to prevent fouling. Using the incorrect heat range can lead to poor performance or engine damage.

Q: Do I need special shorty spark plugs if I install headers on my 350 small block?

A: Yes, in many cases, especially with large-tube aftermarket headers, the clearance between the spark plug boot and the header tubes becomes critically tight. Specialized shorty conventional spark plugs, like the ACCEL models, have a shorter ceramic nose and body to prevent contact and melting of the plug boots.

Q: How often should I replace conventional spark plugs in my 350 small block?

A: Unlike modern engines using long-life iridium plugs, conventional copper plugs should typically be inspected and replaced every 10,000 to 12,000 miles in a street-driven 350 small block. If your engine is highly modified or sees track time, inspections should be done even more frequently, perhaps every oil change, to monitor the heat range and wear pattern.

Q: What are LSI keywords and why are they important for spark plug selection?

A: LSI (Latent Semantic Indexing) keywords are words and phrases related to the main topic (like gap size, conventional spark plugs, heat range, and HEI distributor). They help search engines understand the depth and context of the article. For spark plug selection, understanding these related technical terms helps you choose a plug that correctly matches your specific 350 small block ignition system and modifications.