How many spark plugs does a Hemi got?

A Hemi V8 typically uses 16 spark plugs in total—two spark plugs for each of the eight cylinders. This twin-spark setup is intended to improve ignition reliability and combustion efficiency across the engine family.

What is a Hemi and which models use twin spark?

The Hemi name refers to Chrysler’s hemispherical combustion chamber design used in a range of V8 engines. In modern iterations of the Hemi—such as the 5.7L, 6.1L, 6.4L (392), and 6.2L supercharged variants—the engines employ two spark plugs per cylinder. This arrangement aims to promote faster, more complete combustion, especially given the large bore and high compression common to these engines.

Models typically equipped with 16 spark plugs

The following representative Hemi engines are known to use two spark plugs per cylinder, totaling 16 plugs. There can be exceptions in special editions or market-specific variants.

• 5.7L Hemi V8


• 6.1L Hemi V8


• 6.4L Hemi (392) V8


• 6.2L Hemi (Hellcat/Demon) V8

Note: While the standard production Hemi lineup generally uses two spark plugs per cylinder, always verify the exact configuration for your specific model year and engine code in the owner's manual or with a dealer.

Maintenance considerations

Because there are two spark plugs per cylinder, servicing typically involves replacing 16 spark plugs across the eight cylinders. Replacement intervals vary by model, plug type, and driving conditions; common ranges are roughly 60,000–100,000 miles for many modern plugs. Always follow the factory-recommended interval and torque specs for your engine.

Summary

In short, a modern Hemi V8 generally has 16 spark plugs—two per cylinder—across its eight cylinders. This twin-spark configuration is common to the major Hemi variants, including the 5.7L, 6.1L, 6.4L, and 6.2L (Hellcat) engines, reflecting Chrysler’s ignition strategy for large-bore V8s.

How many spark plugs does a 5.7 Hemi take?

A 5.7L Hemi engine takes 16 spark plugs because it has two spark plugs per cylinder. You will need to remove the ignition coil pack for each cylinder to access the two spark plugs underneath it. 
This video demonstrates the entire process of changing spark plugs on a 5.7L Hemi engine: 1mBoostedMotorsportsYouTube · May 1, 2018

• Quantity: There are 16 spark plugs, with two for each of the eight cylinders. 
• Access: The spark plugs are located beneath the individual ignition coils, which must be removed to get to the plugs. 
• Tools: You will need a 5/8" spark plug socket, various extensions, and likely a torque wrench, anti-seize, and dielectric grease. 

Why do 5.7 Hemis have 16 spark plugs?

The 5.7L Hemi has 16 spark plugs (two per cylinder) to ensure a more complete and efficient combustion, which helps with performance, fuel economy, and emissions. The hemispherical combustion chamber design of the Hemi is prone to leaving unburned fuel, and having two spark plugs ignites the fuel mixture from two points, leading to a faster and more complete burn. This dual-spark ignition helps improve power, reduce engine knock, and meet modern emissions standards. 
This video explains why the HEMI engine uses 16 spark plugs: 58sThe Enthusiast MechanicYouTube · Jul 26, 2024

• Improved combustion: Two points of ignition create a faster and more complete burn of the air-fuel mixture, extracting more energy from the fuel. 
• Better performance: This more efficient burn can result in a slight increase in horsepower and torque, as well as improved throttle response and smoother operation. 
• Lower emissions: By burning the fuel more completely, the engine produces fewer unburned hydrocarbons, which helps it meet stricter emissions regulations. 
• Overcoming design limitations: The unique hemispherical shape of the Hemi's combustion chamber makes it difficult to place a single spark plug in the center. Placing one on each side of the valves compensates for this and ensures a more even burn. 
• Enhanced ignition control: The second spark plug can fire on the power stroke to clean up any remaining emissions or as a "restrike" during the exhaust stroke for a more complete burn and better emissions control. 

This video explains the benefits of twin-spark ignition systems: 46sdriving 4 answersYouTube · Mar 20, 2022

Where are the spark plugs on a 5.7 L Hemi?

Coil. Then we'll remove the coil plug.

How much does it cost to replace spark plugs on a Ram 1500 Hemi?

Replacing the spark plugs on a Ram 1500 Hemi can cost anywhere from $600 to over $1,000, with dealer prices typically ranging from $600-$800 and independent shops potentially around $650-$750. The final cost depends on the specific vehicle model year, the cost of parts (such as iridium or platinum plugs), and the labor rates at the repair shop. 
Cost breakdown

• Parts: The cost of the 16 spark plugs for a Hemi engine will vary. 
  • More affordable options like copper plugs can cost under $4 each, while more expensive and longer-lasting iridium or double-iridium plugs typically range from $8 to $30 each. 
  • You can expect to pay anywhere from around $200 for 16 plugs to over $300, depending on the brand and type you choose. 
• Labor: A Hemi engine has 16 spark plugs, so labor is a significant portion of the cost. 
  • Labor rates can differ between dealerships and independent mechanics. 
  • Some sources report that a dealer can charge between $600 and $800 for the job, while an independent mechanic might charge around $650. 
  • The total cost can exceed $1,000 if the repair is performed at a dealership. 

Where to get a quote

• Dealership: A manufacturer-recommended dealer will use official parts and have manufacturer-trained technicians, but this usually comes with a higher price tag. 
• Independent Mechanic: A general repair shop may be able to perform the service for a slightly lower cost, though prices can still vary widely. 
• Online Estimates: Use online cost calculators from sites like Kelley Blue Book or YourMechanic for a ballpark estimate, but always get a final quote from the repair shop you choose.