1966 GMC L3500 Spark Plugs

Your 1966 GMC L3500 might be the best vehicle you’ve ever owned. Or you may just be struggling to keep it highway-approved. No matter the situation, Advance Auto Parts has the Spark Plugs you desperately need.

We currently carry 22 Spark Plugs to choose from for your 1966 GMC L3500, and our inventory prices range from as little as $2.49 up to $7.49.

On top of low prices, Advance Auto Parts offers 5 different trusted brands of Spark Plugs for the 1966 GMC L3500. We only sell parts from trusted brands like Autolite so that you can find quality parts you can count on.

Don’t take our word for it – check out customer ratings and reviews to buy with confidence. We have 250 reviews on our Spark Plugs for the 1966 GMC L3500 from previous customers.

Have parts delivered straight to your home, or find the nearest Advance Auto Parts store to check out our Spark Plugs stock in-person!

Spark Plugs for Your 1966 GMC L3500

Champion – Copper Plus Spark Plug: Dependable Performance, OE Replacement, RN12YC (Part No.404)

Copper Plus Spark Plug: Dependable Performance, OE Replacement, RN12YC

from

$4.49
Dependable performance. This Champion® spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance and Durability
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Superior corrosion resistance
  • Built to ISO and SAE standards for proven performance
  • Built to ISO and SAE standards for proven performance
See More

Autolite – Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration (Part No.65)

Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration

from

$3.49
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Double Platinum spark plugs feature platinum-to-platinum firing which virtually eliminates gap erosion, reduces misfires and increases durability of the plug. Consider upgrading to Autolite Iridium XP spark plugs for increased performance.

Product Features:
  • Copper cored center electrode for higher thermal conductivity
  • Specially engineered high nickel alloy center and ground electrode for extended life
  • High alumina ceramic for high dielectric strength
  • Leak proof, heat fused internal seal for durability
  • Multi-rib insulator prevents flash-over
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E3 – DiamondFIRE Automotive Spark Plug: More Power, Saves Gas (Part No.E3.52)

DiamondFIRE Automotive Spark Plug: More Power, Saves Gas

from

$6.49
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. E3.52 is a 14mm, 0.375 reach plug with a gasket seat. It fits a wide variety of GM applications from the 50s to early 80s, and is generally the correct plug for older small block Chevrolet engines. 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 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.
See More

ACDelco – Copper Core Spark Plug (Part No.R44XLS)

Copper Core Spark Plug

from

$4.99
ACDelco Professional 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.

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 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
See More

Autolite – Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration (Part No.AP65)

Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration

from

$4.79
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Platinum spark plugs provide a center wire platinum firing tip which provides reduced gap erosion, fewer misfires, better performance and increased durability. Consider upgrading to Autolite Double Platinum or Iridium XP spark plugs for increased performance.

Product Features:
  • High nickel alloy side electrode maintains precise gap
  • Full platinum tip assures virtually no gap erosion for long life
  • Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)
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Autolite – Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration (Part No.AP85)

Platinum Spark Plug: Fires Cleaner, Easier Starts, Quicker Acceleration

from

$4.29
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Platinum spark plugs provide a center wire platinum firing tip which provides reduced gap erosion, fewer misfires, better performance and increased durability. Consider upgrading to Autolite Double Platinum or Iridium XP spark plugs for increased performance.

Product Features:
  • High nickel alloy side electrode maintains precise gap
  • Full platinum tip assures virtually no gap erosion for long life
  • Necked-down center electrode fires quicker, cleaner with less voltage for easier starts, quicker acceleration and improved fuel economy (as compared to standard plugs)
See More

Champion – Copper Plus Small Engine Spark Plug: Dependable Performance, OE Replacement, J6C (Part No.823)

Copper Plus Small Engine Spark Plug: Dependable Performance, OE Replacement, J6C

from

$2.99
Dependable performance. This Champion® spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance and Durability
  • OE type replacement plug
  • Resists fouling
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Superior corrosion resistance
  • Built to ISO and SAE standards for proven performance
See More

Champion – Copper Plus Small Engine Spark Plug Dependable Performance, OE Replacement RN5C (Part No.123)

Copper Plus Small Engine Spark Plug Dependable Performance, OE Replacement RN5C

from

$2.99
Dependable performance. This Champion® spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance and Durability
  • OE type replacement plug
  • Resists fouling
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Superior corrosion resistance
  • Built to ISO and SAE standards for proven performance
See More

Champion – Platinum Power Spark Plug: Powerful Perfromance, OE Replacement, RN14PMC (Part No.3405)

Platinum Power Spark Plug: Powerful Perfromance, OE Replacement, RN14PMC

from

$3.99
Champion® Platinum Power¿ spark plugs deliver powerful performance. Made from exclusive Heat-Active¿ alloy, a fine-wire center electrode and V-trimmed ground electrode provides sharp spark focus.

Product Features:
  • Platinum Power- Premium Spark Plug. Powerful Performance.
  • Platinum center electrode for long life
  • Fine-wire center electrode for greater ignitability
  • V-trimmed ground electrode promotes sharper spark focus
  • Heat-Active┐ alloy allows electrodes to reach optimal temperature
  • Platinum tipped center wire resists wear and helps to maintain proper gap spec over life of the plug
See More

Champion – Copper Plus Small Engine Spark Plug: Dependable Performance, OE Replacement, N5C (Part No.120)

Copper Plus Small Engine Spark Plug: Dependable Performance, OE Replacement, N5C

from

$2.99
Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Resists fouling
  • Superior corrosion resistance
  • Dependable and proven performance
  • Increased conductivity and heat control for good overall wear
See More

Champion – Champion Copper Plus Small Engine- Single Card – J6C (Part No.823-1)

Champion Copper Plus Small Engine- Single Card - J6C

from

$2.49
Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Resists fouling
  • Superior corrosion resistance
  • Dependable and proven performance
  • Increased conductivity and heat control for good overall wear
See More

ACDelco – Copper Core Spark Plug (Part No.R43S)

Copper Core Spark Plug

from

$4.99
ACDelco Professional 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.

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 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
See More

Autolite – Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration (Part No.85)

Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration

from

$3.49
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Double Platinum spark plugs feature platinum-to-platinum firing which virtually eliminates gap erosion, reduces misfires and increases durability of the plug. Consider upgrading to Autolite Iridium XP spark plugs for increased performance.

Product Features:
  • Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leak proof)
  • Multi-rib insulator reduces danger of “flash-over”
  • One-piece terminal post adds strength
  • Resistor reduces radio frequency interference (RFI) and electrode erosion
See More

E3 – DiamondFIRE Automotive Spark Plug: More Power, Saves Gas (Part No.E3.46)

DiamondFIRE Automotive Spark Plug: More Power, Saves Gas

from

$7.49
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 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.
See More

Champion – Copper Plus Spark Plug: Dependable Performance, OE Replacement, RJ12YC (Part No.14)

Copper Plus Spark Plug: Dependable Performance, OE Replacement, RJ12YC

from

$3.99
Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance.
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Patented TinTac and ULTRASEAL coated shell for maximum corrosion resistance
  • Patented SAC-9 semiconductor resistor for maximum EMI & RFI suppression
  • Built to ISO and SAE standards for proven performance
See More

Champion – Copper Plus Small Engine Spark Plug Dependable Performance, OE Replacement J12YC (Part No.10)

Copper Plus Small Engine Spark Plug Dependable Performance, OE Replacement J12YC

from

$3.49
Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance.
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Patented TinTac and ULTRASEAL coated shell for maximum corrosion resistance
  • Patented SAC-9 semiconductor resistor for maximum EMI & RFI suppression
  • Built to ISO and SAE standards for proven performance
See More

Autolite – Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life (Part No.APP65)

Double Platinum Spark Plug: Platinum Firing, Superior Durability, Longer Life

from

$6.49
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Designed and engineered in the USA, Autolite Double Platinum spark plugs feature platinum-to-platinum firing which virtually eliminates gap erosion, reduces misfires and increases durability of the plug. Consider upgrading to Autolite Iridium XP spark plugs for increased performance.

Product Features:
  • Works to optimize engine performance for a longer life and improved fuel economy
  • OE design
  • Full-platinum tips; platinum on both the center and side electrodes to promote reduced gap wear
  • Platinum ball welding process provides a consistent point of contact for enhanced adhesion
See More

Champion – Copper Plus Spark Plug: Dependable Performance, OE Replacement, N12YC (Part No.38)

Copper Plus Spark Plug: Dependable Performance, OE Replacement, N12YC

from

$2.99
Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance.
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Patented TinTac and ULTRASEAL coated shell for maximum corrosion resistance
  • Patented SAC-9 semiconductor resistor for maximum EMI & RFI suppression
  • Built to ISO and SAE standards for proven performance
See More

Autolite – Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration (Part No.404)

Copper Spark Plug: Delivers Quick Starts, Good Fuel Economy, Smooth Acceleration

from

$3.99
Autolite has over 100 years of engineering experience and has sold over 11 billion plugs. Guaranteed to deliver quick starts, good fuel economy and smooth acceleration, Autolite Copper Core spark plugs are designed to meet or exceed OES design requirements. Consider upgrading to Autolite Platinum, Double Platinum or Iridium XP plugs for improved engine performance. Copper core plugs are the industry standard.

Product Features:
  • Copper-glass seal bonds insulator, terminal post center electrode together; assures full required voltage at spark gap; gas-tight seal (100% leak proof)
  • Multi-rib insulator reduces danger of “flash-over”
  • One-piece terminal post adds strength
  • Resistor reduces radio frequency interference (RFI) and electrode erosion
See More

Champion – Copper Plus Spark Plug: Dependable Performance, OE Replacement, RJ6C (Part No.102)

Copper Plus Spark Plug: Dependable Performance, OE Replacement, RJ6C

from

$2.49
Dependable performance. This Champion® spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.

Product Features:
  • Copper Plus – Dependable Performance and Durability
  • Copper core center electrode allows for accurate control of heat range for longer life
  • Superior corrosion resistance
  • Built to ISO and SAE standards for proven performance
  • Built to ISO and SAE standards for proven performance
See More

Autolite – Platinum Spark Plug (Part No.AP404)

Platinum Spark Plug

from

$3.99
Autolite Platinum Spark Plugs provide a center wire platinum firing tip for improved performance.

Product Features:
  • Super conductive Yttrium enhanced ground electrode provides superior heat transfer
  • Full platinum tip assures virtually no gap erosion for longer plug life
  • Leak proof, heat fused resistor for durability
See More

Motorcraft – Spark Plug (AGS42C) (Part No.SP-416)

Spark Plug (AGS42C)

from

$2.49
Motorcraft Spark Plugs are original equipment on Ford Motor Company vehicles engineered to meet strict Ford engineering standards to provide original equipment performance and reliability. Delivering performance, reliability and confidence, Motorcraft spark plugs are available for a broad range of applications, including domestic and import cars and trucks of all makes and sizes.

Product Features:
  • Motorcraft spark plugs are matched to specific engines to provide enhanced durability, eliminate misfires, reduce fuel consumption and optimize emissions.
  • Backed by Motorcraft’s Service Parts Warranty
  • Exact fit for Ford, Lincoln and Mercury vehicles
  • Resistant to oxidation and arc erosion.
  • Multi-rib insulator protects against misfire.
  • Service intervals of up to 100,000 miles.
  • Motorcraft Spark Plugs are designed with high quality materials to provide reliable performance for almost any application.
  • Motorcraft Spark Plugs are what was in the vehicle when it was manufactured
  • Motorcraft ignition components help prevent false check engine lights.
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FAQs for 1966 GMC L3500 Spark Plugs

What are the most popular Spark Plugs for the 1966 GMC L3500?

With 5 brands you can trust, our most popular Spark Plugs for the 1966 GMC L3500 parts are:
Copper Core Spark Plug
from $4.99
(13)
Copper Core Spark Plug
Spark Plugs

What are the best aftermarket Spark Plugs for the 1966 GMC L3500?

See what past customers had to say about our highest-rated Spark Plugs for the 1966 GMC L3500:
DiamondFIRE Automotive Spark Plug: More Power, Saves Gas
from $7.49
(16)
DiamondFIRE Automotive Spark Plug: More Power, Saves Gas
“Comical relief aside, I had a water Fowler plug in my pressure washer and chose to replace it. Washer works great!”
Copper Core Spark Plug
from $4.99
(6)
Copper Core Spark Plug
“Review is not so much about spark plugs, rather Advance Auto Parts, the the great job they do from beginning to end of sale.”