1978 Cadillac Eldorado Spark Plugs

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Keep Your 1978 Cadillac Eldorado in Top Shape with Quality Spark Plugs

Whether you’re repairing or upgrading your Spark Plug, using high-quality parts is key to keeping your 1978 Cadillac Eldorado looking sharp and performing at its best. At Advance Auto Parts we carry a wide selection of dependable options, including Spark Plug Non-Foulers, Spark Plugs, and Spark Plug Wire Set Cut To Fits. Whether you’re replacing a damaged part or enhancing your truck’s style and protection, you’ll find exactly what you need to get the job done right.

Top-Rated Spark Plugs from Trusted Brands

Looking for a reliable Spark Plug? We’ve got you covered with options from brands you know and trust like Autolite, NGK, and Champion. For example, Autolite Spark Plugs start at just $3.99 with an average 4.6 star rating. NGK and Champion offer similar pricing and quality, backed by strong customer feedback. With over 100 reviews and a solid 4 star average, you can shop with confidence knowing other Cadillac Eldorado owners approve.

Explore Related Parts

While you’re upgrading or replacing your Spark Plug, don’t forget to check out other key components like Ignition Boots and Ignition Coils and Boots. At Advance Auto Parts, we’re here to help you keep your 1978 Cadillac Eldorado in peak condition, inside and out.

Essential 1978 Cadillac Eldorado Spark Plugs

ACDelco – Conventional Spark Plug (Part No.R45S)

Conventional Spark Plug

from

$5.99
ACDelco Gold (Professional) Conventional Spark Plugs are a high quality alternative to Original Equipment (OE) parts. These conventional spark plugs are designed for reliability and efficient performance. Their high-quality copper cores and outstanding suppression characteristics deliver reliable performance. They are also available for Marine applications. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.

Product Features:
  • Black Onyx coating helps reduce corrosion
  • Copper core provides great heat transfer and helps maximize plug durability
  • Available for use in Marine applications
  • Some ACDelco Gold parts may have formerly appeared as ACDelco Professional
  • Premium aftermarket replacement part
  • Manufactured to meet specifications for fit, form, and function for General Motors vehicles as well as most makes and models
  • Nickel Center Electrode Tip: Features a nickel center electrode tip for enhanced conductivity and performance.
  • Resistor Type: Equipped with a resistor to help reduce radio frequency interference, ensuring smooth engine operation.
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Accel – Shorty Copper Spark Plug (0437S): Enhanced Clearance & Heat Dissipation (Part No.8197)

Shorty Copper Spark Plug (0437S): Enhanced Clearance & Heat Dissipation

from

$53.99
ACCEL’s patented race proven spark plugs in a Shorty configuration. The overall length has been reduced 3/16 in to 3/8 in (depending on the specific spark plug) to gain critical air gap between the spark plug boot and the exhaust manifold or header tube. This helps eliminate burning the spark plug boot or dimpling the header tube. The shorter spark plug length also can make it easier to install an remove the spark plugs in certain applications where there is not a lot of room to fit a socket or move a wrench around. ACCEL Shorty Spark Plugs are made with a Copper core which is a better conductor than Platinum and Iridium. They deliver a stronger spark especially in high performance applications where high combustion pressures are present. Copper is much better at dissipating heat than other materials which lessens the chance of a misfire. ACCEL Shorty Spark Plugs are capable allowing you to open the gap exposing a larger flame kernel or close it if needed for high boost applications. All ACCEL Shorty Spark Plugs have machine rolled threads allowing for a more precise thread engagement and torque retention.

Product Features:
  • Eliminates Dimpling Headers For Added Clearance
  • Improves Spark Plug Access To Fit Socket Or Wrench
  • Shorter Overall Plug Length Vs. OE Style Plug
  • Copper Core Center Electrode
  • Projected Tip
  • Helps Eliminate Burned Spark Plug Boots
  • Shorty Header Spark Plug
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Autolite Iridium – Iridium XP Fine wire Spark Plug: Improved Durability, More Focused Ignition (Part No.XP64)

Iridium XP Fine wire Spark Plug: Improved Durability, More Focused Ignition

from

$9.99
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, the Autolite Iridium XP spark plugs feature an iridium-enhanced 0.6mm finewire design and patented platinum sidewire technology to provide better overall durability and a more focused ignition for enhanced ignitability and performance. Features double Iridium-enhanced alloy technology center electrode for improved durability and wear resistance.

Product Features:
  • 0.6 mm finewire design improves ignitability
  • Patented V-trimmed platinum sidewire technology resists wear
  • OE equivalent design is engineered for every engine
  • Designed for better overall durability with virtually no gap erosion
  • Double Iridium-enhanced alloy center electrode ensures superior wear resistance for extended performance life.
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Autolite – Platinum Spark Plug (AP605): Enhanced Durability & Performance (Part No.AP605)

Platinum Spark Plug (AP605): Enhanced Durability & Performance

from

$4.99
The Platinum Spark Plug (AP605) is expertly crafted to deliver enhanced durability and performance for older engine applications. Featuring a platinum center electrode firing tip, it ensures quicker firing, smoother starts, and improved fuel efficiency while preventing gap erosion for a longer service life. Its high alumina ceramic insulator provides superior thermal conductivity and insulation, boosting strength and reliability under demanding conditions. The multi-rib insulator design effectively prevents flash-over, while the nickel-plated shell offers exceptional corrosion resistance, extending the plug’s lifespan. With a mid-projection standard center electrode and a tapered seat type, this performance-grade spark plug is built to optimize engine functionality. The combination of platinum and nickel materials in the electrode tips ensures consistent performance and durability, making it a dependable choice for maintaining acceleration and overall engine efficiency.

Product Features:
  • Engineered with a platinum firing tip that prevents gap erosion for longer service life.
  • Its high alumina ceramic insulator provides thermal conductivity and superior insulation for increased strength.
  • The multi-rib insulator prevents flash-over.
  • Designed with a nickel-plated shell that is corrosion resistant to provide increased durability for extended life.
  • Built with a combination of platinum and nickel electrode tips to ensure consistent performance and enhanced durability for maintaining engine efficiency.
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Dorman – Help – Spark Plug Non-Foulers – 14mm Tapered Seat (Part No.42008)

Spark Plug Non-Foulers - 14mm Tapered Seat

from

$10.49
This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.

Product Features:
  • Direct replacement – this spark plug non fouler is designed for easy installation to protect spark plugs from fouling and damage on specified vehicles
  • Ideal solution – this non-fouler preserves spark plug life and is a reliable replacement for an original non-fouler that has failed due to corrosion
  • Durable construction – made from quality components to ensure reliable performance and a long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
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DENSO – Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, ITF16TT (Part No.4715)

Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, ITF16TT

from

$12.99
The Iridium TT Spark Plug combines the durability of an OE-style plug with the power and torque of high-performance engineering. Featuring the world’s smallest 0.4mm Iridium Center Electrode, it maximizes firing potential while the 0.7mm Needle Tip Ground Electrode promotes higher spark energy and minimizes heat quenching. Built with DENSO’s patented Iridium-Rhodium alloy formula, it offers unmatched durability and withstands extreme temperatures exceeding 4000 Deg F. The advanced 360-degree laser welding process ensures a robust bond and structural integrity, while the Twin-Tip Technology, derived from OE Super Ignition Plug design, blends a fine wire Iridium Center Electrode with a Needle Tip Platinum Ground Electrode for ultimate endurance. This spark plug delivers over 100,000 miles of reliable performance, enhanced fuel economy, and reduced emissions, making it an eco-friendly and cost-effective choice. With premium materials and a tapered seat type, the Iridium TT Spark Plug is engineered for optimal performance and long-lasting reliability.

Product Features:
  • 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
  • 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
  • DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Durability of an OE style plug combined with Power and Torque of high performance.
  • Withstands temperatures greater than 4000 degree Fahrenheit
  • Iridium TT
  • Ultimate Endurance and Power: The DENSO Iridium TT Spark Plug features a 0.7mm Iridium Tip, ensuring over 100,000 miles of uncompromised performance.
  • Advanced Twin-Tip Technology: Developed from Original Equipment Specification Super Ignition Plug (SIP) design, combining a Fine Wire Iridium Center Electrode with a Needle Tip Platinum Ground Electrode.
  • Enhanced Fuel Economy and Lower Emissions: Drive around the Earth over 4 times with improved fuel efficiency and reduced emissions.
  • Premium Materials: Features an Iridium Center Electrode Tip and a Tapered Seat Type for optimal performance and durability.
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ACDelco – Conventional Spark Plug (Part No.R45LTS6)

Conventional Spark Plug

from

$5.99
ACDelco GM Original Equipment Conventional Spark Plugs are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These Conventional Spark Plugs are designed for reliability and efficient performance, and are a high quality replacement for many vehicles on the road today. Their high-quality copper cores and outstanding suppression characteristics deliver reliable performance. They are also available for Marine applications. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco GM Original Equipment parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.

Product Features:
  • Black Onyx coating helps reduce corrosion
  • Copper core provides great heat transfer and helps maximize plug durability
  • Ribbed suppressor seal extends resistance and helps prevent spark ‘flash over’ and misfires
  • Nickel-chrome alloy sheathing helps prevent corrosion on center electrode
  • Available for use in Marine applications
  • Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional
  • ACDelco GM Original Equipment parts are designed, engineered and tested to rigorous standards, and are backed by General Motors
  • GM Engineers design and validate OE parts specifically for your Chevrolet, Buick, GMC, or Cadillac vehicle
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Autolite – Double Platinum Spark Plug: Enhanced Durability & Performance (Part No.APP104)

Double Platinum Spark Plug: Enhanced Durability & Performance

from

$6.99
Double Platinum Spark Plug: Enhanced Durability & Performance is engineered for exceptional reliability and efficiency, making it a top choice for distributor-less ignition system (DIS) engines. Featuring a platinum-to-platinum design, it minimizes gap erosion and reduces misfires, ensuring consistent performance and extended service life. The yttrium-enhanced ground electrode offers superior heat transfer, allowing the spark plug to withstand high temperatures and pressures for greater durability. Its high alumina ceramic insulator optimizes thermal conductivity and dielectric strength, while the multi-rib insulator prevents flash-over for added safety and reliability. With a mid-projection center electrode and tapered seat type, this performance-grade spark plug delivers precision and compatibility. Both the center and ground electrode tips are crafted from platinum, ensuring long-lasting efficiency and superior ignition performance. Designed to outperform copper and standard platinum plugs, this spark plug is a durable and high-value solution for maintaining peak engine performance.

Product Features:
  • Engineered with a platinum-to-platinum design that prevents gap erosion, extending the life of the spark plug.
  • The yttrium-Enhanced Ground Electrode delivers superior heat transfer that delivers more durability under high temps and pressure for greater life.
  • Its high alumina ceramic insulator provides optimum thermal conductivity and dielectric strength.
  • The multi-rib insulator prevents flash-over.
  • Designed with a mid-projection center electrode and tapered seat type for enhanced precision and compatibility with distributor-less ignition system (DIS) engines.
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DENSO – Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, IT16TT (Part No.4713)

Iridium TT Spark Plug: Ultimate Endurance and Power, 0.4mm Iridium Tip, IT16TT

from

$13.99
The Iridium TT Spark Plug combines the durability of an OE-style plug with the power and torque of high-performance engineering, making it a standout choice for drivers seeking reliability and efficiency. Featuring a 0.4mm Iridium center electrode – the world’s smallest diameter – it maximizes firing potential, while the 0.7mm needle tip ground electrode promotes higher spark energy and minimizes heat quenching. Built with DENSO’s patented Iridium-Rhodium alloy formula, it boasts the highest concentration of Iridium for unmatched durability, withstanding temperatures over 4000 Deg F. The advanced Twin-Tip Technology pairs a fine wire Iridium center electrode with a needle tip Platinum ground electrode, ensuring superior ignition and fuel efficiency. Designed to enhance fuel economy and reduce emissions, this spark plug allows you to drive farther with fewer stops. Developed to original equipment specifications and utilizing a 360-degree laser welding process, it guarantees exceptional structural strength and consistent performance. Perfect for those who demand endurance and power in every drive.

Product Features:
  • 0.4mm Iridium Center Electrode: World’s Smallest Diameter that maximizes firing potential
  • 0.7mm Needle Tip Ground Electrode: Promotes higher spark energy and less heat quenching
  • DENSO Patented Optimized Iridium-Rhodium Alloy Formula: Highest concentration of Iridium vs. competitors for greater durability
  • DENSO Patented 360 degree laser welding process: Ensuring exceptional quality bond and structural strength with the Iridium Center Electrode
  • Durability of an OE style plug combined with Power and Torque of high performance.
  • Withstands temperatures greater than 4000 degree Fahrenheit
  • Iridium TT
  • Advanced Twin-Tip Technology: Combines a Fine Wire Iridium Center Electrode with a Needle Tip Platinum Ground Electrode for superior ignition and efficiency.
  • Enhanced Fuel Economy and Lower Emissions: Designed to provide better fuel economy and reduced emissions, allowing you to drive around the Earth over 4 times.
  • Original Equipment Specification: Developed from the Super Ignition Plug (SIP) design, ensuring reliable and consistent performance.
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Dorman – Help – Spark Plug Non-Foulers – 14mm Tapered Seat (Part No.42006)

Spark Plug Non-Foulers - 14mm Tapered Seat

from

$7.59
This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.

Product Features:
  • Direct replacement – this spark plug non fouler is designed for easy installation to protect spark plugs from fouling and damage on specified vehicles
  • Ideal solution – this non-fouler preserves spark plug life and is a reliable replacement for an original non-fouler that has failed due to corrosion
  • Durable construction – made from quality components to ensure reliable performance and a long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
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Dorman – Help – Spark Plug Non-Foulers – 14mm Gasket Seat Long Reach (Part No.42004)

Spark Plug Non-Foulers - 14mm Gasket Seat Long Reach

from

$9.99
This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.

Product Features:
  • Direct replacement – this spark plug non fouler is designed for easy installation to protect spark plugs from fouling and damage on specified vehicles
  • Ideal solution – this non-fouler preserves spark plug life and is a reliable replacement for an original non-fouler that has failed due to corrosion
  • Durable construction – made from quality components to ensure reliable performance and a long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
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Dorman – Help – Spark Plug Non-Foulers – 14mm Gasket Seat (Part No.42000)

Spark Plug Non-Foulers - 14mm Gasket Seat

from

$7.99
This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.

Product Features:
  • Direct replacement – this spark plug non fouler is designed for easy installation to protect spark plugs from fouling and damage on specified vehicles
  • Ideal solution – this non-fouler preserves spark plug life and is a reliable replacement for an original non-fouler that has failed due to corrosion
  • Durable construction – made from quality components to ensure reliable performance and a long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
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Accel – Universal Fit Super Stock 8mm Suppression; Spark Plug Wire Set (Part No.4040R)

Universal Fit Super Stock 8mm Suppression; Spark Plug Wire Set

from

$73.99
These ACCEL wire sets are a true performance upgrade replacement for OE types. Efficient delivery of spark energy for a good price. Silicone boots with black wire contain zinc-plated steel terminals. Noise suppression core. Set contains 8 plug wires with coil lead.

Product Features:
  • 7mm And 8mm High Gloss Silicone Jacket
  • 450° F Rated Silicone Jacket
  • Stainless Steel Plug Terminals
  • RFI Suppression For Street Driven Applications
  • Custom-fit Universal And Import Coverage
  • High-strength Fiberglass Braid Construction
  • Pre And Post HEI Vehicles
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MSD Ignition – Wire Set; Super Conductor; 8-cyl. Multi-Angle Plug; Socket/HEI (Part No.31199)

Wire Set; Super Conductor; 8-cyl. Multi-Angle Plug; Socket/HEI

from

$143.99
Set includes terminals for engines with early type (socket) and late type (HEI spark plug top) distributor caps. 90 degree boots and terminals factory installed on one end.

Product Features:
  • Extra Long 8.5mm Wires So You Can Cut To Your Designed Length
  • Incl. both socket-style and spark plug-style boots and terminals
  • Includes Mini-Stripper-Crimper For Factory Style Crimps
  • Size Includes: [2]48/50/56 in./[3] 32 in. Wires/Boots/Terminals
  • Durable outer sleeve is a proprietary compound for resistance to high heat or abrasion
  • Stainless steel terminals feature dual crimp tabs to grip wire conductor and outer jacket separately
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Most Popular Spark Plug Non-Fouler for 1978 Cadillac Eldorados

Enhance your 1978 Cadillac Eldorado with this popular Spark Plug Non-Fouler we have in stock, for $9.99.

Dorman – Help – Spark Plug Non-Foulers – 14mm Gasket Seat Long Reach (Part No.42004)

Spark Plug Non-Foulers - 14mm Gasket Seat Long Reach

from

$9.99
This spark plug non fouler is designed for easy installation on specified vehicles to protect spark plugs from fouling and damage. It is engineered for durability and reliable performance.

Product Features:
  • Direct replacement – this spark plug non fouler is designed for easy installation to protect spark plugs from fouling and damage on specified vehicles
  • Ideal solution – this non-fouler preserves spark plug life and is a reliable replacement for an original non-fouler that has failed due to corrosion
  • Durable construction – made from quality components to ensure reliable performance and a long service life
  • Trustworthy quality – backed by team of product experts in the United States and more than a century of automotive experience
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Best-Selling 1978 Cadillac Eldorado Spark Plugs

Upgrade your Eldorado with one of our 9 best-selling Spark Plugs, earning an average 4.58 stars rating across 43 reviews.

Champion – Double Platinum Power Spark Plug (RN14PMP5): Enhanced Ignitability & Durability (Part No.7031)

Double Platinum Power Spark Plug (RN14PMP5): Enhanced Ignitability & Durability

from

$9.99
Champion Double Platinum Power spark plugs are engineered for superior performance and durability, making them an ideal choice for standard replacement needs. Featuring a platinum fine-wire center electrode and a platinum pad ground electrode, these spark plugs deliver exceptional wear resistance and maintain stable operating temperatures under all engine loads. The innovative Heat-Active alloy ensures the electrodes reach optimal temperature quickly, enhancing efficiency and reliability. With a V-trimmed ground electrode design, these spark plugs promote sharper spark focus for improved ignitability and smoother engine operation. Designed with a flat seat type and integrated resistor, they provide consistent performance while reducing electrical interference. Perfect for drivers seeking enhanced ignitability and long-lasting durability, these spark plugs are built to meet the demands of modern engines.

Product Features:
  • Double Platinum Power – Premium Spark Plug. More Powerful Performance.
  • Platinum center and ground electrode for greater wear resistance
  • Maintains stable operating temperature under all engine loads
  • Fine-wire center electrode for greater ignitability
  • V-trimmed ground electrode promotes sharper spark focus
  • Heat-Active alloy allows electrodes to reach optimal temperature
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NGK – V-Power Nickel Spark Plug (GR45): Enhanced Ignitability & Performance (Part No.4268)

V-Power Nickel Spark Plug (GR45): Enhanced Ignitability & Performance

from

$6.99
NGK V-Power spark plugs offer reliable performance and improved ignitability over standard nickel plugs. Engineered specifically for OE applications, the special V-cut nickel alloy center electrode and concave ground electrode of NGK’s V-Power spark plug increases ignitability providing quicker starts and smoother idle. NGK’s legendary high grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance. Trivalent metal plating ensures superior anti-corrosion and anti-seizing properties.

Product Features:
  • ACTUAL OE or EQUIVALENT DESIGN: OEM quality construction nickel alloy center electrode with V-groove provides consistent performance
  • RECOMMENDED USAGE: Best for vehicles with OE nickel alloy plugs, not recommended on vehicles with factory precious metal plugs
  • NGK’s OE CERAMIC TECHNOLOGY: High grade alumina silicate ceramic creates a stronger insulator for optimal dielectric performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • TRIVALENT METAL PLATING: Delivers superior anti-corrosion and anti-seizing properties, ensuring ease of installation and removal
  • Enhanced Ignitability: The V-cut nickel alloy center electrode and concave ground electrode design of NGK V-Power spark plugs provide quicker starts and smoother idle.
  • OE Application Specific: Engineered specifically for Original Equipment (OE) applications, ensuring compatibility and reliable performance.
  • V-Groove Tip Design: The unique V-Groove tip design of the GR45 model enhances ignitability and overall engine performance.
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Autolite – Double Platinum Spark Plug: Enhanced Durability & Performance (Part No.APP646)

Double Platinum Spark Plug: Enhanced Durability & Performance

from

$6.99
Double Platinum Spark Plug offers enhanced durability and performance with its platinum-to-platinum design, effectively reducing gap erosion and misfires for a longer service life. Engineered for distributor-less ignition system (DIS) engines, it outperforms copper and standard platinum plugs. The yttrium-enhanced ground electrode ensures superior heat transfer, maintaining durability under high temperatures and pressure. Its high alumina ceramic insulator optimizes thermal conductivity and dielectric strength, while the multi-rib insulator prevents flash-over for reliable operation. Featuring a mid-projection center electrode and flat seat type, this performance-grade spark plug is built with platinum tips on both the center and ground electrodes for consistent ignition and efficiency. Designed to withstand demanding conditions, it delivers exceptional value for drivers seeking reliability and long-lasting performance.

Product Features:
  • Engineered with a platinum-to-platinum design that prevents gap erosion, extending the life of the spark plug.
  • The yttrium-Enhanced Ground Electrode delivers superior heat transfer that delivers more durability under high temps and pressure for greater life.
  • Its high alumina ceramic insulator provides optimum thermal conductivity and dielectric strength.
  • The multi-rib insulator prevents flash-over.
  • Designed with a mid-projection center electrode and flat seat type to ensure consistent ignition and optimized performance in demanding conditions.
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Autolite – Copper Resistor Spark Plug: Quick Starts & Enhanced Durability (Part No.646)

Copper Resistor Spark Plug: Quick Starts & Enhanced Durability

from

$3.99
Autolite Copper spark plugs are designed to provide reliable performance and durability for your vehicle. Featuring a copper core center electrode, these spark plugs excel in thermal control and resist fouling, ensuring consistent operation. The high nickel alloy center and ground electrodes are engineered for extended life, while the mid-projection design optimizes spark delivery. A high alumina multi-rib ceramic insulator enhances thermal conductivity and insulation, offering superior strength under demanding conditions. The nickel-plated shell resists corrosion, adding to the plug’s longevity. With a flat seat type and built-in resistor, these spark plugs are a dependable choice for maintaining quick starts and meeting your vehicle’s performance needs.

Product Features:
  • The copper core center electrode aids in thermal control and improves resistance to fouling.
  • Its specially engineered high nickel alloy center and ground electrode provides extended life.
  • The high alumina multi-rib ceramic insulator provides thermal conductivity and superior insulation for increased strength.
  • Designed with a nickel-plated shell that is corrosion resistant to provide increased durability for extended periods.
  • The mid-projection design of the center electrode ensures optimized spark delivery for consistent and efficient engine performance.
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E3 – DiamondFire Spark Plug (E3.46): Enhanced Power & Fuel Efficiency (Part No.E3.46)

DiamondFire Spark Plug (E3.46): Enhanced Power & Fuel Efficiency

from

$8.49
The Spark Plugs are the product of years of fundamental research in the combustion field. The unique patented electrode configuration of these new The spark plugs increases the amount of combustion pressure created during each power stroke of an engine, which results in a marked increase in power output, fuel economy, and reduced emissions in all gasoline engines. E3.46 is a 14mm, 0.750 reach plug with a gasket seat. It fits a wide variety of applications from the 60s to early 90s, especially import. E3.46 is widely stocked in automotive retail stores. The automotive plugs have three legs securing the Diamond FIRE electrode to the shell. This allows for excellent heat transfer, and helps to create more turbulence in the cylinder. The patented Diamond FIRE side wire is proven to increase power, reduce fuel consumption and improve hydrocarbon emissions in long-term use.

Product Features:
  • E3’s Diamond Fire edge to edge ground electrode provides maximum performance with increased efficiency and a faster more complete burn.
  • Smoother Acceleration & Idle – The faster flame initiated by the spark plug results in a more complete burn of the ingested fuel charge. More pressure is created against the piston more fuel is put to work
  • Energy – Power output improved up to 6% on average in the typical operating ranges. Results will vary.
  • Efficiency – The “diamond shaped” side wire electrode projects the combustion spark in a way that more quickly ignites the air/fuel mixture, thereby creating a significantly faster and larger flame kernel. The result is that more fuel is put to work durin
  • E3’s patented Diamond Fire Technology provides a cleaner burning combustion, which translates into fuel savings and reduced engine carbon deposits
  • The Spark Plugs are pre-gapped at the factory and cannot be adjusted.
  • Wide Compatibility: The E3.46 spark plugs are 14mm with a 0.750 reach and a gasket seat, making them suitable for a wide range of applications from the 1960s to early 1990s, especially for import vehicles.
  • Widely Available: The E3.46 spark plugs are widely stocked in automotive retail stores, ensuring easy availability for consumers.
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Autolite – Platinum Spark Plug: Enhanced Durability & Improved Performance (Part No.AP646)

Platinum Spark Plug: Enhanced Durability & Improved Performance

from

$4.99
Autolite Platinum spark plugs are expertly crafted to deliver exceptional performance and durability for older engine applications. Featuring a platinum center electrode firing tip, these spark plugs resist gap erosion, ensuring a longer service life and consistent reliability. The high alumina ceramic insulator enhances thermal conductivity and insulation, providing superior strength under demanding conditions. A multi-rib insulator design prevents flash-over, while the nickel-plated shell offers outstanding corrosion resistance for extended durability. With a necked-down center electrode, these spark plugs fire quicker and cleaner, requiring less voltage for smoother starts, faster acceleration, and improved fuel efficiency. Designed with a mid-projection standard center electrode and a flat seat type, they are tailored for performance-grade applications. The combination of platinum and nickel materials ensures optimal conductivity and durability, making these spark plugs a smart choice for drivers seeking enhanced engine efficiency and long-lasting reliability.

Product Features:
  • Engineered with a platinum firing tip that prevents gap erosion for longer service life.
  • Its high alumina ceramic insulator provides thermal conductivity and superior insulation for increased strength.
  • The multi-rib insulator prevents flash-over.
  • Designed with a nickel-plated shell that is corrosion resistant to provide increased durability for extended life.
  • Necked-down center electrode fires quicker and cleaner with less voltage for easier starts, quicker acceleration, and improved fuel economy
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ACDelco – RAPIDFIRE Spark Plug (Part No.4)

RAPIDFIRE Spark Plug

from

$7.99
ACDelco Gold (Professional) RAPIDFIRE Spark Plugs are a high quality alternative to Original Equipment (OE) parts. These RAPIDFIRE Single Platinum Performance Spark Plugs are designed for everyday use and are a high quality replacement for many vehicles on the road today. These premium aftermarket spark plugs have high-quality suppressors that help prevent misfiring, an improved plug to boot seal, and a pure copper core for greater durability. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco Gold (Professional) parts are manufactured to meet your expectations for fit, form, and function, making them a smart choice for General Motors vehicles, as well as most makes and models, including special applications. These high-quality parts are backed by General Motors. Some ACDelco Gold parts may have formerly appeared as ACDelco Professional.

Product Features:
  • Solid state suppressor, with two-piece glass and brass seal, can help reduce radio frequency interference, regulates spark energy for long electrode life, and helps protect against high combustion pressures
  • Pure copper core provides great heat transfer and helps maximize plug durability
  • Platinum on center electrode enables superior spark characteristics and can reduce voltage requirements of the ignition system
  • Ribless insulator helps optimize plug to boot seal
  • Some ACDelco Gold parts may have formerly appeared as ACDelco Professional
  • Premium aftermarket replacement part
  • Manufactured to meet specifications for fit, form, and function for General Motors vehicles as well as most makes and models
  • High-Quality Suppressors: These spark plugs are equipped with high-quality suppressors that help prevent misfiring, ensuring smooth and efficient engine operation.
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ACDelco – Conventional Spark Plug (Part No.R45XLS6)

Conventional Spark Plug

from

$5.99
ACDelco GM Original Equipment Conventional Spark Plugs are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These Conventional Spark Plugs are designed for reliability and efficient performance, and are a high quality replacement for many vehicles on the road today. Their high-quality copper cores and outstanding suppression characteristics deliver reliable performance. They are also available for Marine applications. These premium aftermarket replacement spark plugs are manufactured to meet your expectations for fit, form, and function. ACDelco GM Original Equipment parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles. Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional.

Product Features:
  • Black Onyx coating helps reduce corrosion
  • Copper core provides great heat transfer and helps maximize plug durability
  • Ribbed suppressor seal extends resistance and helps prevent spark ‘flash over’ and misfires
  • Nickel-chrome alloy sheathing helps prevent corrosion on center electrode
  • Available for use in Marine applications
  • Some ACDelco GM Original Equipment parts may have formerly appeared as GM Genuine Parts (OE) or ACDelco Professional
  • ACDelco GM Original Equipment parts are designed, engineered and tested to rigorous standards, and are backed by General Motors
  • GM Engineers design and validate OE parts specifically for your Chevrolet, Buick, GMC, or Cadillac vehicle
  • GM regularly updates production and service part designs to integrate new materials and technologies
  • High-Quality Copper Core: ACDelco Professional Conventional Spark Plugs feature high-quality copper cores, ensuring reliable performance and efficient operation.
  • Nickel Center Electrode Tip: Designed with a nickel center electrode tip, these spark plugs provide durability and consistent performance.
  • Outstanding Suppression Characteristics: These spark plugs offer excellent suppression characteristics, contributing to their reliable performance in various driving conditions.
  • Premium Aftermarket Replacement: Manufactured to meet expectations for fit, form, and function, these spark plugs serve as a high-quality replacement for original equipment.
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NGK – G-Power Platinum Spark Plug (GR45GP): Enhanced Durability & Efficiency (Part No.3142)

G-Power Platinum Spark Plug (GR45GP): Enhanced Durability & Efficiency

from

$5.99
NGK G-Power Platinum spark plugs are the best single platinum spark plugs at an economical price. G-Power plugs feature a fine wire platinum center electrode and a trapezoidal cut ground electrode that offers increased durability, improved fuel efficiency, lower emissions, faster starts and quicker acceleration over conventional nickel spark plugs. An excellent upgrade for vehicles which used nickel alloy spark plugs originally. For better performance consider upgrading to a NGK Iridium IX plug. For even greater performance consider upgrading to a NGK RUTHENIUM HX plug.

Product Features:
  • SINGLE PLATINUM TIP: Fine wire 0.6 millimeter platinum tip center electrode ensures improved durability and a consistently stable spark
  • PLATINUM ALLOY: G-Power platinum provides exceptional value with increased performance and longer service intervals than factory nickel plugs
  • TRAPEZOIDAL CUT GROUND ELECTRODE: Reduces quenching design produces improved ignitability and performance
  • SOLID COPPER CORE: 98% pure copper core offers superior heat dissipation, conductivity and ultra wide heat ranges
  • COLD-ROLLED THREADS: Prevents cross-threading and damage to cylinder heads
  • RECOMMENDED USAGE: Lower cost alternative to double precious metal spark plugs or as an upgrade to OE nickel alloy spark plugs
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Top-Quality Spark Plug Wire Set Cut To Fits for 1978 Cadillac Eldorados

Choose a high-quality OEM or aftermarket Spark Plug Wire Set Cut To Fit for Cadillac Eldorados and enjoy top-notch performance from $73.99.

MSD Ignition – Wire Set; Super Conductor; 8-cyl. Multi-Angle Plug; Socket/HEI (Part No.31199)

Wire Set; Super Conductor; 8-cyl. Multi-Angle Plug; Socket/HEI

from

$143.99
Set includes terminals for engines with early type (socket) and late type (HEI spark plug top) distributor caps. 90 degree boots and terminals factory installed on one end.

Product Features:
  • Extra Long 8.5mm Wires So You Can Cut To Your Designed Length
  • Incl. both socket-style and spark plug-style boots and terminals
  • Includes Mini-Stripper-Crimper For Factory Style Crimps
  • Size Includes: [2]48/50/56 in./[3] 32 in. Wires/Boots/Terminals
  • Durable outer sleeve is a proprietary compound for resistance to high heat or abrasion
  • Stainless steel terminals feature dual crimp tabs to grip wire conductor and outer jacket separately
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Accel – Universal Fit Super Stock 8mm Suppression; Spark Plug Wire Set (Part No.4040R)

Universal Fit Super Stock 8mm Suppression; Spark Plug Wire Set

from

$73.99
These ACCEL wire sets are a true performance upgrade replacement for OE types. Efficient delivery of spark energy for a good price. Silicone boots with black wire contain zinc-plated steel terminals. Noise suppression core. Set contains 8 plug wires with coil lead.

Product Features:
  • 7mm And 8mm High Gloss Silicone Jacket
  • 450° F Rated Silicone Jacket
  • Stainless Steel Plug Terminals
  • RFI Suppression For Street Driven Applications
  • Custom-fit Universal And Import Coverage
  • High-strength Fiberglass Braid Construction
  • Pre And Post HEI Vehicles
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Top-Rated Spark Plug Brands For Your 1978 Cadillac Eldorado

When it comes to finding the perfect Spark Plug for your 1978 Cadillac Eldorado, Advance Auto Parts has you covered with a wide selection of high-quality OEM and aftermarket options from 8 trusted brands. We carry the most popular Spark Plug brands including NGK, Champion, and Autolite, and more, all known for their exceptional customer ratings (average brand rating of 4.8 stars) and competitive prices, as low as $3.99. Purchasing a Spark Plug from us here at Advance Auto Parts is a smart move for both you and your 1978 Cadillac Eldorado, providing peace of mind with parts that meet or exceed OEM standards.

Popular NGK 1978 Cadillac Eldorado Spark Plugs

If you’re looking for a top-quality Spark Plug for your 1978 Cadillac Eldorado, Advance Auto Parts has exactly what you need with our selection of NGK Spark Plugs. We have 1 NGK Spark Plugs in stock for this fitment, all known for their durability and precision fit. With prices starting at just $6.99, you’ll find the perfect Spark Plug for your needs and budget. NGK Spark Plugs for the 1978 Cadillac Eldorado come highly rated, with over 4 customer reviews and an impressive average rating of 4.8 stars. Choosing a NGK Spark Plug from Advance Auto Parts is a smart move to ensure quality and value for your vehicle.

Top-Quality Champion 1978 Cadillac Eldorado Spark Plugs

For those in search of a high-quality Spark Plug for their 1978 Cadillac Eldorado, Advance Auto Parts offers a great selection of Champion Spark Plugs. With 1 Champion Spark Plugs in stock, you can trust you’re getting top-tier parts designed for durability and a perfect fit. Prices for these Spark Plugs start at just $9.99, giving you a range of options to suit your budget. Backed by over 8 customer ratings and an average rating of 4.7 stars, Champion Spark Plugs provide both reliability and excellent performance. Choosing a Champion Spark Plug from Advance Auto Parts is a smart investment in your vehicle’s performance and longevity.

FAQs for 1978 Cadillac Eldorado Spark Plugs

What are the best-selling Spark Plugs for 1978 Cadillac Eldorados?

Out of 12 Spark Plugs that fit 1978 Cadillac Eldorados, the following parts are the top sellers:

What’s the price range for 1978 Cadillac Eldorado Spark Plugs?

The prices of Spark Plugs for the 1978 Cadillac Eldorado range from $3.99 up to $143.99 for the most premium parts.

What is the average price of a Spark Plug for a 1978 Cadillac Eldorado?

The average price for Spark Plugs for the 1978 Cadillac Eldorado is $24.12. Keep in mind the variety of part types within our Spark Plug category, where you are likely to find a wide range of prices across a variety of parts and components.

Does Advance Auto Parts sell Spark Plugs for other Cadillac Eldorado model years?

Yes, we carry Spark Plugs for 48 model years of Cadillac Eldorados between 1953 and 2002. The following model years are the most popular for Spark Plug purchases: 2002, 2001, 2000, 1999, 1998, 1997, 1996, 1995, and 1994.

What are the cheapest Spark Plugs for my 1978 Cadillac Eldorado?

Does Advance Auto Parts sell Spark Plugs for any other 1978 Cadillac models?

Yes. We stock Spark Plugs for 3 other popular 1978 Cadillac models. Some of the most popular are 1978 DeVille Spark Plugs, 1978 Seville Spark Plugs, 1978 Fleetwood Spark Plugs, and 1978 Commercial Chassis Spark Plugs.

What are the top-rated Spark Plugs that fit the 1978 Cadillac Eldorado?

Based on 100 reviews by customers, our 1978 Cadillac Eldorado Spark Plugs have an average customer rating of 4 stars. These are the highest-rated categories of Spark Plugs for the 1978 Cadillac Eldorado and their top-rated products:

What types of Spark Plugs do you sell for my 1978 Cadillac Eldorado?

As of 3/1/26, these are some of the most in-demand types of Spark Plugs for a 1978 Cadillac Eldorado:

Can I get help with 1978 Cadillac Eldorado Spark Plug orders?

Contact our customer support team by chat or phone, through the help desk page, where you can find instant answers about Cadillac Spark Plugs and more.

What is your return policy for Cadillac Eldorado Spark Plugs?

Advance Auto Parts keeps returns simple. For new Cadillac Eldorado Spark Plugs and accessories, your online orders can be returned, in their original condition, within 45 days. For requirements, see the returns page.