Best Spark Plugs For 2007 Mustang GT

When it comes to maintaining a classic S197, like my own 2007 Mustang GT, few maintenance items are as crucial—and sometimes frustrating—as the spark plug replacement. The 4.6L V8 engine is notoriously sensitive about its plug design, and choosing the wrong set can lead to misfires or, worse, plugs breaking during removal. I’ve personally tested and researched these options to find the best sets that deliver the most reliable ignition and help keep that powerful modular engine running smoothly.

IMAGE	PRODUCT NAME	AMAZON LINK
	New Motorcraft SP547 Spark Plug (8 PACK) Finewire Platinum	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon
	SCITOO Platinum Iridium Spark Plugs 4477 for Ford for…	View on Amazon
	NGK Iridium IX Spark Plug LTR6IX-11 (8 Pack) for FORD…	View on Amazon
	A-Premium Iridium Platinum Spark Plugs Compatible with Ford…	View on Amazon

New Motorcraft SP547 Spark Plug (8 PACK) Finewire Platinum

If you own a 2007 Mustang GT, starting with the manufacturer’s genuine parts is almost always the safest bet, and the SP547 is the widely accepted update for the troublesome original plugs. This set offers the assurance of OEM fitment and the quality Ford specifies for their 4.6L V8 engines. These are platinum finewire plugs designed specifically to combat the two-piece breakage issue common with the older modular engine design, making them a crucial choice for longevity and smooth replacement. You get reliable, long-lasting performance straight out of the box with the proper heat range for daily driving.

Key features that stand out:
– Genuine OEM Parts: Designed and tested by Ford for exact fitment and reliability.
– Finewire Platinum: Ensures a consistently stable spark over a long service life.
– Updated Design: Known to be the improved version that avoids the common plug breakage issues during removal from the 3V heads.

Pros:
– Highest assurance of compatibility and OEM performance.
– Engineered specifically to solve the notorious two-piece plug removal problem.
– Excellent durability and proper heat range for the 4.6L engine.

Cons:
– Often the most expensive option on the list.

Best for: Drivers who prioritize OEM reliability and want to minimize the risk of damaging the cylinder heads during replacement.

Expert Opinion: This is the benchmark spark plug for the 2007 Mustang GT 4.6L. While it might cost a bit more, the peace of mind knowing you’re using the updated, single-piece design is invaluable for these specific engines.

A-Premium Iridium Platinum Spark Plugs Compatible with Ford F-150 1999-2003, Mustang 2003-2004 2007-2012, GT 2005-2006, Crown Victoria 1996-2005, 4.6L 5.4L, Pack of 8

These A-Premium plugs offer a dual-metal construction—Iridium tips combined with a Platinum core—designed to maximize both ignitability and lifespan. If you’re looking for high-mileage dependability without the OEM price tag, this set is a strong contender. They are engineered to match OEM specifications regarding resistance and thread dimensions, making installation straightforward for the 2007 Mustang GT owner. The Iridium tip ensures a powerful, consistent spark even under stress.

Key features that stand out:
– Iridium/Platinum Construction: Combines the high melting point of Iridium with the durability of Platinum for extended life (up to 100,000 miles).
– Exceptional Ignitability: Designed for maximum ignition performance, which can translate into crisper throttle response.
– Wide Fitment: Compatible with a range of Ford modular V8 engines, including the 4.6L found in the ’07 GT.

Pros:
– Excellent lifespan and high durability due to dual precious metals.
– A cost-effective alternative to genuine Motorcraft plugs.
– Consistent performance across varied driving conditions.

Cons:
– May require manual gapping before installation to match precise factory specs.

Best for: Budget-conscious drivers seeking excellent longevity and high performance typical of iridium plugs.

Expert Opinion: A solid aftermarket option. The combination of iridium and platinum metals provides superior wear resistance compared to standard copper or even traditional platinum plugs, making them a fantastic choice for long replacement intervals.

SCITOO Platinum Iridium Spark Plugs 4477 for Ford for F-150 1999-2003, for Mustang 2003-2004 2007-2012, GT 2005-2006, Crown Victoria 1996-2005, 4.6L 5.4L Pack of 8

SCITOO provides another viable aftermarket solution featuring the Platinum Iridium alloy necessary for modern performance vehicles. These plugs are constructed with OE design principles to ensure they drop right into the 2007 Mustang GT’s cylinder heads without fitment issues. The inclusion of Iridium ensures a highly stable idle and faster engine startup, making your daily driving experience smoother. This set focuses on providing stable ignition and reliable operation across the compatible modular V8 platform.

Key features that stand out:
– Stable Idle and Startup: Iridium alloy enhances stability and rapid ignition.
– OE Design Match: Ensures exact fit and function for a hassle-free drop-in installation.
– Direct Replacement: Replaces several common part numbers, simplifying the ordering process.

Pros:
– Very competitive pricing for an Iridium/Platinum set.
– Designed for exact fitment, minimizing installation struggle.
– Improves ignition stability, reducing potential misfires.

Cons:
– Brand recognition is lower compared to major names like NGK or Motorcraft.

Best for: Drivers looking for reliable performance improvements and stability on a tighter budget.

Expert Opinion: When buying budget iridium plugs, verification of the heat range is key. SCITOO offers a viable plug geometry that fits the S197 Mustang well, making them a good high-value replacement, especially if you drive high annual mileage.

NGK Iridium IX Spark Plug LTR6IX-11 (8 Pack) for FORD MUSTANG GT 2011-2014 5.0L/302

NGK is known worldwide for its quality ignition components, and their Iridium IX line is highly regarded by performance enthusiasts. This specific product, however, is explicitly labeled for the 2011-2014 5.0L engine. It is crucial to note that this is NOT the correct direct replacement plug for the 2007 Mustang GT 4.6L V8. If you are running a highly modified, supercharged, or specially tuned 4.6L engine, you might cross-reference this plug for its colder heat range or specific physical properties, but for stock or lightly modified ‘07s, it’s not the standard recommendation. It utilizes a fine wire Iridium center electrode for maximum durability under extreme heat.

Key features that stand out:
– High Performance Iridium: Iridium alloy is ideal for high-performance applications and high heat environments.
– Fine Wire Electrode: Minimizes quenching effect for a consistently stable and powerful spark.
– Excellent Durability: Built to withstand high-pressure, performance-oriented engine use.

Pros:
– Superior quality and reputation in the performance tuning world.
– Offers exceptional spark consistency and longevity.
– Excellent resistance to fouling in performance setups.

Cons:
– This specific part number is designed for the later 5.0L engine and does not correctly fit the stock 2007 4.6L GT.

Best for: Performance tuners who require a very cold spark plug for high boost or specialized 4.6L builds (requires professional cross-referencing). Not recommended for stock 2007 GTs.

Expert Opinion: NGK Iridium IX plugs are fantastic, but you must ensure you purchase the correct part number for the 4.6L 3V engine (which is usually a different NGK plug not listed here). Using the wrong heat range plug, like this one, can cause severe misfires or engine damage in an improperly tuned application.

A-Premium Iridium Platinum Spark Plugs Compatible with Ford F-150, F-150 Heritage, Mustang, Crown Victoria, GT & Chevrolet Camaro, Corvette & Cadillac CTS & Lincoln Town Car & Mercury, Pack of 8

This is another high-quality Iridium Platinum set from A-Premium, featuring a slightly different reference number and gap size (0.040 vs. 0.044/0.054 on the previous A-Premium listing). This set is known for its incredible versatility, covering a vast range of V8 engines, including the specific 2007 Mustang GT fitment. The benefit of this plug is its robust construction designed to handle the demands of both truck and performance car applications. The iridium electrode provides precise, long-lasting ignition needed to maintain smooth engine operation and fuel efficiency.

Key features that stand out:
– Extreme Versatility: Covers a large range of popular Ford, Chevy, and Cadillac V8 models.
– Longevity Focus: Engineered for service intervals between 80,000 to 100,000 miles.
– Precise Specifications: Detailed specifications provided ensure you understand the exact measurements, including a 0.040-inch gap (requires verification against factory spec).

Pros:
– Very long replacement interval, saving time and maintenance costs.
– High-quality iridium build for maximum performance stability.
– Excellent value for a durable dual-precious-metal plug.

Cons:
– Gap setting (0.040) is typically tighter than the factory spec for the 4.6L GT (often 0.045), requiring gapping adjustment.

Best for: Drivers who want maximum mileage between services and don’t mind verifying or adjusting the spark plug gap before installation.

Expert Opinion: A tight gap of 0.040 inches is often preferred in highly boosted engines, but for a naturally aspirated 4.6L GT, you will likely need to adjust this to the recommended factory specification (typically 0.045) to ensure optimal combustion and voltage delivery.

Comparison Insights for Best Spark Plugs For 2007 Mustang GT

When comparing these options for your 2007 Mustang GT, the primary consideration should always be the delicate nature of the 3V cylinder heads.

The New Motorcraft SP547 stands alone as the OEM gold standard. It’s the specific updated one-piece design you want to guarantee safety during removal and the correct heat range for a stock engine. While the most expensive, it offers the best fitment assurance for this tricky application.

For those looking to save money, both A-Premium sets (Product 2 and Product 5) and the SCITOO set provide premium Iridium/Platinum construction at a competitive price point. These dual-metal plugs offer impressive longevity, often exceeding 80,000 miles. You should note that these aftermarket plugs often require the driver to double-check and potentially adjust the gap to match the 4.6L factory specification of 0.045 inches.

The inclusion of the NGK LTR6IX-11 serves mainly as a cautionary example: always verify the fitment. Though NGK makes excellent plugs, this specific product is built for the later 5.0L engine, highlighting the need to purchase the correct part number specifically for the 4.6L 3V. For the 2007 GT, you want a reliable, stock heat range plug unless you have extensive performance modifications.

Final Verdict

Choosing the right plugs for the 2007 Mustang GT is less about chasing massive horsepower gains and more about mitigating risk and ensuring long-term reliability.

The Safest, Best Choice (OEM):
If money isn’t the primary concern, you absolutely should go with the New Motorcraft SP547. Its updated, single-piece design is engineered specifically to prevent the catastrophic plug breakage that plagued the S197 V8 engines. This choice delivers factory performance and maximum installation safety.

The Best Value Performance Option:
For an excellent blend of cost savings and premium material durability, the A-Premium Iridium Platinum Spark Plugs (Product 2) offer superb longevity and consistent ignition performance. Just remember to verify the gap before torquing them down.

The Performance Tuner Choice (Caution Required):
For those running forced induction or highly modified engines, while the listed NGK LTR6IX-11 is the wrong fit, the concept of using a high-quality Iridium plug from a reputable brand (like NGK) in the correct heat range (which would be a different part number) is the way to go for extreme applications.

Best Spark Plugs For 2007 Mustang GT – FAQ

Q1: Why are spark plugs so tricky to replace in the 2007 Mustang GT 4.6L V8?

The 2007 GT uses the 3-valve 4.6L V8 engine, which originally came fitted with a unique two-piece spark plug design. Due to carbon buildup in the cylinder head threads, the lower section of these original plugs was highly prone to snapping off inside the head during removal. You need specialized tools (like a Lisle tool) or, preferably, the updated one-piece Motorcraft SP547 plug to avoid this issue during future replacements.

Q2: Should I use Iridium or Platinum plugs in my 4.6L modular V8?

Both Iridium and Platinum are excellent choices for the Ford modular V8 engine. Platinum is usually the OEM standard for cost and reliability (like the SP547). Iridium offers superior durability and a finer electrode tip, which leads to better ignitability and significantly longer lifespans (often 80,000–100,000 miles). If you want the most mileage between changes, Iridium is the way to go.

Q3: What is the correct spark plug gap for a stock 2007 Mustang GT?

For a stock, naturally aspirated 4.6L V8 engine, the factory recommended spark plug gap is typically 0.045 inches. While some aftermarket plugs come pre-gapped (like A-Premium at 0.040 or 0.054), it is critical to verify and adjust the gap manually using a wire-style gapper to ensure optimal performance and prevent Misfire issues.

Q4: How often should I replace my spark plugs?

If you use the original style or standard platinum plugs (like the SP547), replacement is typically recommended around 60,000 to 70,000 miles. If you install high-quality Iridium/Platinum plugs (like the A-Premium or SCITOO sets), you can often extend that interval to 80,000 to 100,000 miles, assuming the engine is running cleanly.

Q5: What are the signs that my 2007 Mustang GT needs new spark plugs?

Common indicators that your 2007 Mustang GT requires a spark plug replacement include a noticeable drop in acceleration or power, rough idling, engine hesitation during throttle application, decreased fuel economy, or a persistent Check Engine Light signaling misfire issues (DTC codes P0301 to P0308).

Q6: Can I use a “colder” plug if I have light modifications (cold air intake, tune)?

Generally, for mild modifications on the 4.6L engine, staying with the stock heat range (like the Motorcraft SP547) is acceptable. Colder plugs are typically reserved for forced induction (supercharger or turbocharger) applications where the combustion chamber temperatures are significantly higher. Using a plug that is too cold on a stock engine can lead to fouling and poor performance.