Best Spark Plugs for 350 Chevy Engine

Alright, let’s talk about the heart of your classic 350 Chevy engine – its ignition system, specifically the spark plugs. As someone who’s spent countless hours under the hood of these legendary small blocks, I know firsthand the difference a good set of spark plugs can make. It’s not just about getting the engine to start; it’s about optimizing everything from fuel efficiency and idle smoothness to raw horsepower and overall engine reliability. Choosing the best spark plugs for your 350 Chevy engine can feel a bit overwhelming with so many options out there, from traditional copper to advanced iridium. But don’t worry, I’ve dug deep into some top contenders, including a few essential spark plug wire sets, to help you make an informed decision. We’re going to break down their features, benefits, and drawbacks, giving you the practical insights you need to get your 350 purring like a kitten or roaring like a beast, depending on what you’re after.

IMAGE	PRODUCT NAME	AMAZON LINK
	NGK V Power Spark Plug UR4 (8 Pack) for CHEVROLET…	View on Amazon
	ACDelco CR43TS 5614029 (05614029) Professional Conventional…	View on Amazon
	Universal Spark Plug Wire Set – 8.5mm Red High…	View on Amazon
	NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8…	View on Amazon
	JDMSPEED New 10.5mm Spark Plug Wire Set Replacement for…	View on Amazon
	CNPAPC 8PCS Iridium SBC Spark Plugs & 9PCS Spark Plug…	View on Amazon
	LLANNDER 10mm High Performance Spark Plug Wire Set…	View on Amazon
	64602 High Energy 8mm Spark Plug Wires Set Replacement…	View on Amazon
	High Performance Low Resistance 10.5MM HEI Spark Plug Wire…	View on Amazon
	ACDelco 41-962 Professional Platinum Spark Plug, (8)	View on Amazon

Our Top Picks for Your 350 Chevy Engine

Here’s a detailed look at some of the best spark plugs and compatible wire sets that can make a real difference in your 350 Chevy.

1. NGK V Power Spark Plug UR4 (8 Pack) for CHEVROLET…

When it comes to tried-and-true performance for your classic Chevy small block, the NGK V-Power UR4 spark plugs are a fantastic baseline. I’ve used these in several carbureted 350s, and they consistently deliver reliable spark and smooth operation. These aren’t fancy, but their copper core is excellent for conductivity, ensuring a strong spark for consistent combustion. The V-groove center electrode is a neat trick, channeling the spark to reduce misfires and improve ignitability. They’re built with a nickel alloy tip and a projected insulator for better resistance to fouling, which is especially good if your engine tends to run a little rich or sees a lot of idle time. Plus, they come in an 8-pack, so you’re ready to swap out all your plugs at once.

Key features that stand out:
– Copper Core: Excellent electrical conductivity for a strong, reliable spark.
– V-Groove Center Electrode: Improves ignitability and reduces misfires.
– Projected Insulator Type: Helps resist carbon buildup and fouling.
– Resistor Type: Prevents radio frequency interference (RFI).

Pros:
– Great value and performance for the price.
– Excellent conductivity from the copper core.
– Reliable for stock and mildly modified engines.
– Helps maintain good fuel efficiency.

Cons:
– Not as long-lasting as platinum or iridium plugs.

Best for: Daily drivers and stock to mildly modified 350 Chevy engines looking for reliable performance on a budget.

Expert Opinion: These NGK V-Power plugs are a workhorse. They’re a solid, dependable choice that often outperforms their price point, especially if you’re keen on regular maintenance.

2. ACDelco CR43TS 5614029 (05614029) Professional Conventional…

For those who appreciate OEM quality and straightforward reliability, the ACDelco CR43TS is a go-to. ACDelco is GM’s original equipment brand, so you know these plugs are designed to spec for your 350 Chevy. I often recommend these for restorers or anyone wanting to keep things as close to factory as possible. The copper core ensures great heat transfer, which is crucial for durability and consistent performance. What’s really neat is the ribbed suppressor seal, which does a fantastic job preventing spark flash-over and misfires, contributing to a smoother running engine. And let’s not forget the black onyx coating, a nice touch that actively fights corrosion, extending the plug’s life.

Key features that stand out:
– Copper Core Thermal Properties: Excellent heat transfer and increased durability.
– Ribbed Suppressor Seal: Prevents spark flash-over and misfires.
– Black Onyx Coating: Offers superior corrosion prevention.
– Available for Marine Applications: Indicates robustness and reliability.

Pros:
– OEM quality ensures perfect fit and function.
– Excellent corrosion resistance for longer life.
– Reliable spark delivery for smooth engine operation.
– Good for both automotive and marine use.

Cons:
– Not a performance-enhancing plug; more suited for stock applications.

Best for: Restorations, daily drivers, and anyone seeking factory-level reliability and longevity for their 350 Chevy.

Expert Opinion: You can’t go wrong with ACDelco for a stock setup. These plugs are consistent, durable, and deliver exactly what your 350 needs without any fuss.

3. Universal Spark Plug Wire Set – 8.5mm Red High…

Now, while we’re talking about spark plugs, we can’t forget about the wires that deliver that crucial spark! This universal 8.5mm red high-performance wire set is designed for HEI (High Electronic Ignition) systems common in many 350 Chevy engines. I’ve found that upgrading wires can be just as impactful as new plugs, especially if your old wires are breaking down. These come with a spiral wound design and heavy-duty silicone jackets that protect against heat, oil, and abrasion – things your engine bay sees a lot of. The high-temperature black boots provide excellent heat resistance, while the stainless steel and brass terminals ensure fantastic conductivity. It’s a complete package to ensure maximum spark delivery for a variety of small and big block Chevy engines.

Key features that stand out:
– 8.5mm Spiral Wound Design: Enhances conductivity and suppresses interference.
– Heavy Duty Silicone Jackets: Superior resistance to heat, oil, and abrasion.
– High-Temperature Black Boots: Provides excellent heat and oil resistance for durability.
– Universal HEI Fitment: Compatible with a wide range of SBC (350 included) and BBC engines.

Pros:
– Significantly improves spark delivery to plugs.
– Highly durable and resistant to harsh engine conditions.
– Easy to install with 90-degree boots.
– Comes with a 12-month warranty for peace of mind.

Cons:
– May require some minor length adjustment for a truly custom fit.

Best for: Any 350 Chevy owner with an HEI distributor looking to upgrade their ignition system for improved performance and reliability.

Expert Opinion: Don’t overlook your wires! These 8.5mm wires are a solid upgrade for HEI systems, ensuring that the powerful spark your distributor creates actually makes it to your plugs efficiently.

4. NGK # 3186 G-Power Platinum Spark Plugs TR5GP – 8…

Stepping up from traditional copper, the NGK G-Power Platinum plugs offer enhanced durability and performance, especially for engines that see varied driving conditions. I like these because they provide a noticeable improvement in longevity and often a crisper throttle response compared to standard copper plugs. The platinum alloy tip is much harder and more resistant to erosion, allowing for a finer wire center electrode. This design helps the plug operate efficiently across a much wider heat range, making them excellent for engines that might see both heavy traffic and open-road cruising. The triple gasket sealing process is a testament to NGK’s quality, completely eliminating combustion gas leakage, which is critical for consistent performance.

Key features that stand out:
– G-Power Platinum Electrode: Offers superior durability and a finer tip for better ignitability.
– Wider Heat Range Operation: Adapts better to varied engine conditions and temperatures.
– Triple Gasket Sealing: Prevents combustion gas leakage for consistent performance.
– Resists Carbon Buildup and Pre-Ignition: Helps maintain optimal engine health.

Pros:
– Longer lifespan than copper plugs.
– Improved throttle response and smoother idle.
– Excellent resistance to fouling and pre-ignition.
– High-quality construction and sealing.

Cons:
– More expensive than standard copper plugs.

Best for: 350 Chevy engines seeking an upgrade in longevity and slightly improved performance over conventional plugs, especially for daily drivers or mild street performance.

Expert Opinion: Platinum plugs like these NGK G-Powers are a great sweet spot between cost and performance. They’re a noticeable upgrade in durability and maintain a clean burn longer than copper.

5. JDMSPEED New 10.5mm Spark Plug Wire Set Replacement for…

If you’re serious about getting every bit of spark to your plugs, especially with a performance-oriented 350 Chevy, this JDMSPEED 10.5mm wire set is definitely worth a look. I’ve often seen thicker wires like these make a difference in engines running higher compression or hotter coils. The 10.5mm thickness isn’t just for show; it houses a robust spiral-wound conductor designed to minimize resistance and maximize voltage delivery. These are specifically for HEI systems on small and big block Chevy engines and come ready for install straight out of the box, with various wire lengths to accommodate different engine bay layouts. The heavy-duty insulation protects against engine heat and electrical interference, ensuring a strong, consistent spark.

Key features that stand out:
– 10.5mm Racing Spark Plug Wires: Extra thick for maximum voltage delivery and minimal resistance.
– Ready for Install: Pre-cut lengths for convenience (though checking fitment is always smart).
– Universal HEI Fitment: Compatible with a wide range of SBC (350 included) and BBC engines.
– High-Performance Construction: Designed for demanding ignition systems.

Pros:
– Delivers maximum available spark energy to the plugs.
– Excellent for performance applications and hotter coils.
– Durable construction resists heat and interference.
– Pre-cut lengths simplify installation for many setups.

Cons:
– May be overkill for a completely stock, low-performance engine.

Best for: Performance-minded 350 Chevy owners with HEI distributors, especially those running hotter coils or seeking to extract every last bit of power from their ignition system.

Expert Opinion: When you need serious spark delivery, 10.5mm wires like these step up to the plate. They’re built for performance and ensure your plugs get all the juice they need.

6. CNPAPC 8PCS Iridium SBC Spark Plugs & 9PCS Spark Plug…

This CNPAPC set is a fantastic option if you’re looking for a complete ignition overhaul for your 350 Chevy. It combines 8 iridium spark plugs with a 9-piece spark plug wire set, giving you a powerful, long-lasting, and efficient ignition system right out of the box. Iridium plugs are known for their incredibly fine electrodes and extreme durability, offering superior ignitability and a lifespan that can often exceed 90,000 km. Paired with dual high-temp silicone jacket wires that feature fiberglass reinforcement, you’re getting maximum spark delivery without interference. This combo is designed for both SBC and BBC GM V8 engines, including your 350, ensuring enhanced combustion efficiency, smoother starts, and improved fuel economy.

Key features that stand out:
– Iridium Spark Plugs: Fine-wire electrode for enhanced ignitability and extremely long lifespan (90,000+ km).
– Complete Kit: Includes 8 iridium plugs and a 9-piece wire set (8 plug wires, 1 coil wire).
– Durable Spark Plug Wires: Dual high-temp silicone jacket with fiberglass reinforcement for wear, moisture, and corrosion resistance.
– Enhanced Combustion Efficiency: Leads to smoother starts and improved fuel economy.

Pros:
– Comprehensive ignition upgrade in one package.
– Iridium plugs offer superior performance and longevity.
– Wires ensure stable current and maximum spark delivery.
– Direct fit and easy installation with a 12-month warranty.

Cons:
– Investment cost is higher due to the complete kit.

Best for: 350 Chevy owners looking for a comprehensive, high-performance, and long-lasting ignition system upgrade, especially those who want the best in ignitability and durability.

Expert Opinion: This combo package is a smart move for anyone wanting to fully refresh their ignition. Iridium plugs with quality wires deliver a consistent, powerful spark and last a very long time.

7. LLANNDER 10mm High Performance Spark Plug Wire Set…

Another excellent choice for beefing up your 350 Chevy’s ignition is this LLANNDER 10mm High Performance Spark Plug Wire Set. These wires are all about ensuring maximum energy transfer and protecting against the harsh realities of the engine bay. I’ve seen how crucial robust wires are for performance engines, and these fit the bill with their high-grade silicone insulator, stranded copper core, and fiberglass braided layer, all wrapped in a heavy-duty silicone jacket. This construction means they can withstand extremely high temperatures and prevent any current leakage or short-circuiting. They’re a 9-piece kit, including the coil wire, with convenient 90-degree boots on both ends, making installation straightforward for HEI distributors on both SBC and BBC engines. Expect smoother startups, improved horsepower, and better fuel efficiency.

Key features that stand out:
– Upgraded 10mm Design: High-grade silicone insulator, stranded copper core, and fiberglass braided layer for durability.
– Withstands Extreme Temperatures: Prevents current leakage and short-circuiting.
– Easy Installation: 9-piece kit (8 plug, 1 coil) with 90-degree boots.
– Improved Performance: Promotes smooth start-up, effective RFI suppression, and enhanced horsepower/fuel efficiency.

Pros:
– Superior construction for maximum durability and heat resistance.
– Ensures highest possible energy delivery to spark plugs.
– Helps suppress RFI, crucial for onboard electronics.
– Noticeable improvements in engine performance.

Cons:
– Like other high-performance wires, they’re not the cheapest option.

Best for: 350 Chevy engines with HEI distributors, especially those seeking maximum performance, improved reliability, and excellent protection against engine bay elements.

Expert Opinion: These 10mm wires are a great way to ensure your ignition system is delivering its full potential. The robust construction means they’ll handle the heat and vibrations of a performance 350 with ease.

8. 64602 High Energy 8mm Spark Plug Wires Set Replacement…

For those looking for a reliable replacement or a slight upgrade without breaking the bank, the 64602 High Energy 8mm Spark Plug Wires Set is a solid choice for your 350 Chevy. These are a good middle-ground, offering better performance than ancient stock wires but without the extreme thickness of racing wires. The 8mm wires are specifically designed for 8-cylinder engines from 1974-1988 Chevy/GM models, making them a perfect fit for many classic 350s. They feature heat and oil resistant blue 100% silicone boot ends with double spring locking terminals, ensuring a secure connection and long life. The universal kit allows for flexibility in boot ends, accommodating various spark plug cover styles. These are a great way to ensure a consistent, strong spark.

Key features that stand out:
– 8mm Spark Plug Wires: Good balance of conductivity and durability for a wide range of applications.
– Heat and Oil Resistant Wires: 100% silicone boot ends for durability in harsh conditions.
– Double Spring Locking Terminals: Ensures secure connections and prevents dislodgement.
– Universal Kit Flexibility: Accommodates 90°, 135°, or 180° spark plug boot ends.

Pros:
– Reliable and durable replacement for older, worn-out wires.
– Good value for a performance-oriented upgrade.
– Resists heat and oil effectively.
– Wide compatibility with older Chevy/GM V8 engines.

Cons:
– Not as thick or high-performance as 10.5mm wires.

Best for: 350 Chevy owners needing a durable, reliable spark plug wire replacement or a mild performance upgrade for models from 1974-1988.

Expert Opinion: These 8mm high-energy wires are a practical and effective upgrade. They’ll definitely improve spark delivery over old, cracked wires and offer good value for money.

9. High Performance Low Resistance 10.5MM HEI Spark Plug Wire…

Another heavy-duty contender in the spark plug wire category is this High Performance Low Resistance 10.5MM HEI Spark Plug Wire set. If you’ve got an HEI distributor in your 350 Chevy and want to ensure every joule of energy reaches your spark plugs, these are engineered for that purpose. I’ve found that thicker wires like these are crucial for mitigating resistance and maintaining voltage, especially in high-demand ignition systems. These wires boast a pure silicone insulator outer layer and a heavy-duty silicone sheath with high-temperature black boots, all designed to withstand extreme heat and voltage. This robust construction means your engine can consistently operate at maximum potential power without long-term performance degradation. They also come with specific fitment for a wide range of classic Chevy vehicles, making compatibility easier.

Key features that stand out:
– 10.5mm Spark Plug Wires: Maximum voltage delivery with low resistance.
– Pure Silicone Insulator & Sheath: Withstands extreme heat and voltage.
– HEI Design Specific: Black 90-degree boots for HEI distributors.
– Wide Vehicle Fitment: Compatible with a long list of classic Chevy models.

Pros:
– Optimizes ignition performance by minimizing energy loss.
– Extremely durable and resistant to engine bay stressors.
– Designed for HEI systems, ensuring proper fit and function.
– Comprehensive vehicle fitment list helps with selection.

Cons:
– Might be an aesthetic challenge in some highly stock engine bays.

Best for: 350 Chevy engines running HEI distributors, especially those in classic cars with a broad range of years, where maximizing spark energy and durability is a priority.

Expert Opinion: For a performance HEI setup, these 10.5mm wires are a smart upgrade. They’re built to last and deliver consistent, strong spark, which translates directly to better engine response.

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

Rounding out our spark plug selection, the ACDelco 41-962 Professional Platinum Spark Plugs offer an excellent blend of OEM quality and enhanced durability for your 350 Chevy. These are a step up from conventional copper, featuring a double platinum point pad on both the center and ground electrodes. This design provides superb durability and consistent voltage demands, which helps reduce wear on your entire ignition system – a crucial long-term benefit. I appreciate their one-piece, fired-in suppressor seal, which blends three glass types for a gas-tight seal, effectively reducing radio frequency interference and protecting against high compression pressures. The pure copper core still ensures cooler electrode temperatures, maximizing durability and resistance to fouling.

Key features that stand out:
– Double Platinum Point Pad: Excellent durability and consistent voltage, reducing ignition system wear.
– One-Piece, Fired-in Suppressor Seal: Reduces RFI, regulates energy, and protects against compression.
– Pure Copper Core: Ensures cooler electrode temperature for maximized durability and fouling resistance.
– ACDelco Professional Grade: OEM quality with enhanced features.

Pros:
– Exceptional durability and extended service life.
– Reduces wear on other ignition components.
– Excellent resistance to fouling and RFI.
– Maintains consistent performance over time.

Cons:
– Higher initial cost compared to conventional plugs.

Best for: 350 Chevy owners who prioritize long-term durability, consistent performance, and reduced maintenance intervals, seeking an OEM-quality platinum upgrade.

Expert Opinion: These ACDelco Platinum plugs are a fantastic choice for those who want a set-it-and-forget-it solution. They offer great durability and reliability, perfect for a daily driver or a well-maintained classic.

Comparison Insights: Making the Right Choice for Your 350 Chevy

When you’re looking for the best spark plugs for your 350 Chevy engine, it’s clear there’s more than just one factor to consider. We’ve seen a mix of actual spark plugs and spark plug wire sets, and understanding how they work together is key to maximizing your engine’s performance.

Spark Plug Materials: Copper vs. Platinum vs. Iridium
* Copper plugs like the NGK V Power UR4 and ACDelco CR43TS are your budget-friendly workhorses. They offer excellent conductivity for a strong, consistent spark and are a great choice for stock to mildly modified engines, especially if you don’t mind changing them more frequently (typically every 10,000-20,000 miles). They’re fantastic for pure electrical performance right out of the box.
* Platinum plugs, such as the NGK G-Power Platinum TR5GP and ACDelco 41-962 Professional Platinum, offer a significant step up in durability. The platinum alloy resists erosion much better than copper, allowing for a finer electrode and a longer lifespan (often 30,000-60,000 miles). They often provide a crisper throttle response and better resistance to fouling. They’re an excellent mid-range option for those seeking longevity without the higher cost of iridium.
* Iridium plugs, exemplified by the CNPAPC Iridium SBC Spark Plugs, are the premium choice. With the finest electrodes and highest melting point, iridium plugs deliver the most consistent and powerful spark over the longest duration (often 80,000-100,000+ miles). They provide the best ignitability, contributing to smoother starts, better fuel economy, and optimal combustion efficiency. If ultimate longevity and peak performance are your goals, iridium is the way to go.

Spark Plug Wires: The Unsung Heroes
It’s crucial to remember that even the best spark plugs are only as good as the wires that feed them power. We’ve reviewed several wire sets: the Universal Spark Plug Wire Set (8.5mm Red), JDMSPEED (10.5mm), CNPAPC’s included wires, LLANNDER (10mm), 64602 High Energy (8mm), and the High Performance Low Resistance (10.5mm).
* Wire Thickness Matters: Thicker wires, like the 10mm and 10.5mm sets from JDMSPEED, LLANNDER, and High Performance Low Resistance, generally indicate lower resistance and a greater ability to deliver maximum voltage to your spark plugs, making them ideal for performance applications or engines with hotter coils.
* Material and Construction: Look for wires with silicone jackets and boots for superior heat, oil, and abrasion resistance. Features like spiral-wound conductors and fiberglass reinforcement (seen in many of the reviewed wire sets) are key for efficient spark delivery and durability.
* HEI Compatibility: Most of the reviewed wire sets are designed specifically for HEI (High Electronic Ignition) distributors, which are very common in 350 Chevy engines. Ensure the boots and lengths are compatible with your specific HEI setup.

Budget vs. Performance vs. Longevity
* If you’re on a tighter budget but still want reliable performance, pairing copper plugs (like NGK V-Power) with a good 8mm or 8.5mm wire set (like the 64602 or Universal Red) is a smart play.
* For a balanced approach offering better longevity and consistent performance, a platinum plug (like NGK G-Power or ACDelco Platinum) with a robust 8.5mm or 10mm wire set will serve you well.
* If peak performance and maximum lifespan are your top priorities, investing in iridium plugs, especially in a combo kit like the CNPAPC offering, coupled with a high-performance 10mm or 10.5mm wire set, will give your 350 Chevy the best possible ignition system.

Remember, a strong, consistent spark is fundamental to your 350’s overall health and performance. Don’t underestimate the impact that both quality spark plugs and robust wires can have!

Final Verdict: Igniting Your 350 Chevy’s Potential

After diving deep into these options, it’s clear that finding the best spark plugs for your 350 Chevy engine isn’t a one-size-fits-all answer. It truly depends on your specific needs, driving style, and budget.

• For the everyday driver or budget-conscious restorer, you can’t go wrong with the NGK V Power Spark Plug UR4 or the ACDelco CR43TS Conventional Plugs. Pair them with a reliable and affordable wire set like the 64602 High Energy 8mm for a solid, no-nonsense ignition system. These choices offer excellent value and consistent performance for a stock setup.

• If you’re looking for a significant upgrade in durability and slightly enhanced performance, without going full race spec, the NGK G-Power Platinum TR5GP or the ACDelco 41-962 Professional Platinum are fantastic choices. Combine these with a durable, mid-range wire set like the Universal Spark Plug Wire Set 8.5mm Red for an excellent balance of longevity and improved spark.

• For the performance enthusiast or anyone seeking the absolute best in longevity and ignitability, the CNPAPC 8PCS Iridium SBC Spark Plugs & 9PCS Spark Plug Wires kit stands out as a top-tier, all-in-one solution. If you want maximum spark delivery from your HEI, a heavy-duty wire set like the JDMSPEED New 10.5mm Spark Plug Wire Set or the LLANNDER 10mm High Performance Spark Plug Wire Set would be my pick. These options will ensure your 350 Chevy is getting the most powerful and consistent spark possible, translating to improved horsepower, fuel economy, and a smoother-running engine.

Ultimately, whether you’re chasing every last horsepower or simply want a reliable daily driver, choose the spark plugs and wires that align with your engine’s current state and your future goals. A well-maintained ignition system is paramount to your 350 Chevy’s legendary performance and longevity.

Comprehensive FAQ Section

Q1: What exactly does “350 Chevy engine” refer to, and why is spark plug choice important?
A1: The “350 Chevy engine” typically refers to the Chevrolet small-block V8 engine with a 350 cubic inch (5.7L) displacement. It’s one of the most iconic and widely used engines ever produced by General Motors, found in countless cars and trucks from the mid-60s through the early 2000s. Choosing the best spark plugs for your 350 Chevy engine is crucial because they initiate combustion. A good plug ensures an efficient, powerful spark, leading to better fuel economy, smoother idle, more horsepower, and reduced emissions. Poor spark plugs can cause misfires, rough running, and wasted fuel.

Q2: What’s the main difference between copper, platinum, and iridium spark plugs for a 350 Chevy?
A2: The primary difference lies in the electrode material and design, impacting lifespan and ignitability.
* Copper: Excellent conductivity for a strong spark but softer, leading to shorter lifespans (10-20k miles). Cost-effective and good for older engines.
* Platinum: Harder than copper, allowing for a finer electrode and longer lifespan (30-60k miles). Offers good ignitability and durability, often a good upgrade.
* Iridium: The hardest metal used, enabling the finest electrodes. Provides the best ignitability, most consistent spark, and longest lifespan (80-100k+ miles). Offers peak performance and fuel efficiency.

Q3: How often should I change the spark plugs in my 350 Chevy engine?
A3: This depends heavily on the type of spark plug you’re using and your engine’s condition.
* Copper plugs: Generally every 10,000 to 20,000 miles.
* Platinum plugs: Can last 30,000 to 60,000 miles.
* Iridium plugs: Often rated for 80,000 to 100,000+ miles.
Always check your vehicle’s owner’s manual or the spark plug manufacturer’s recommendations. For a classic 350 Chevy, regular inspection is key.

Q4: Do spark plug wires matter as much as the spark plugs themselves for a 350 Chevy?
A4: Absolutely! Spark plug wires are vital components of your ignition system. They deliver the high voltage from the ignition coil to the spark plugs. Worn, cracked, or low-quality wires can cause resistance, leading to a weak spark, misfires, poor fuel economy, and reduced performance, even if you have the best spark plugs for your 350 Chevy engine. Upgrading to a high-quality, low-resistance wire set, especially for HEI systems, ensures maximum spark delivery.

Q5: What’s the proper spark plug gap for a 350 Chevy?
A5: The proper gap can vary based on your specific 350 Chevy setup, including the year, ignition system (points, HEI, aftermarket electronic), and any modifications. A common starting point for a stock HEI 350 is usually around 0.045 inches (or .045″). However, it’s always best to check your vehicle’s service manual or the spark plug manufacturer’s recommendations for your specific engine and plug type. Incorrect gapping can lead to misfires or reduced performance.

Q6: Can I use performance spark plugs (like iridium) in a stock 350 Chevy engine?
A6: Yes, you absolutely can! While performance plugs might offer more benefits to modified engines, even a stock 350 Chevy will benefit from the enhanced ignitability, smoother idle, and significantly longer lifespan that premium iridium or platinum plugs provide. You might notice a slightly crisper throttle response and improved fuel efficiency. They’re a great “set it and forget it” option for any 350 Chevy owner.