skip to content

How Many Spark Plugs Does a 5.7 Hemi Have: 80% Don’t Know

What spark plugs are important? Spark plugs are essential parts of your car or truck, and even a 5.7 Hemi Engine is not an exception.

They are one of the most overlooked components of your vehicle. If they fail, your engine won’t start. That means you’ll have to spend time and money fixing it.

Do you know How many Spark Plug Any Diesel Engine has? Explore here!

So, How Many Spark Plugs Does a 5.7 Hemi Have? Let’s explore!

To know the exact answer, we must know what a 5.7 Hemi Engine is!

What is a 5.7 Hemi Engine?

The 5.7L engine was a brand original engine, designed entirely from scratch. Similar to its predecessor, the 4.7L PowerTech V8. The 345 Hemi engine features a cast-iron block for cylinders with a deep skirt design and an angle of 90 degrees between the banks of cylinders.

The crankshaft, made of nodular cast iron, is mounted by four bolts for the main bearing. It comes with powdered metal connecting rods forged and skirt-coated pistons.

How Many Spark Plugs in a 5.7L Hemi?

There are a total of 16 Spark Plugs in 5.7 Hemi Engines

Each 5.7 Hemi engine has two spark plugs in each aluminum cross-flow cylinder heads along with two valves for each cylinder. The HEMI-shaped chambers are now an elongated design, with shelves squished on both sides to improve efficiency and reduce emissions.

The camshaft controls the exhaust and intake valves via pushrods using the rocker’s arms. The engine also comes with beehive valve springs and roller-type hydraulic lifters. Cylinder-deactivation system named MDS (Multi-Displacement Systems) is the classic feature of 5.7 Hemi Engines that helps in reducing fuel consumption as well as emissions.

The system shuts off gas in all four of the one cylinder (two within each of the banks) and ensures that the exhaust and intake valves shut to control the oil flow through the lifters on the respective valves.

The size of the intake valves is 2.00 inches (50.8 millimeters), while the exhaust valves’ diameter is 1.55 inches (39.4 millimeters). Intake manifolds are constructed out of plastic. It also has an electronic throttle body (drive-by-wire).

Is 5.7 Hemi Any Good?

The 5.7 Hemi is the most powerful production V8 engine ever sold. This engine has been used in various cars such as Challenger, Charger, 2023 Ram 1500 Truck,  Chrysler 300C, etc.

Chrysler is one of the biggest automobile companies in the US. 5.7 Hemi Engine by them is an excellent engine that comes with incredible horsepower

How to Buy A Right Spark Plug for 5.7 Hemi?

The spark plug’s role is crucial, so it should be chosen carefully. Here are some tips to help you choose the correct spark plug for 5.7 Hemi’s:

Check the Spark Plug Gap

The gap between the spark plug’s electrodes is essential because this determines how much energy will be transferred to the air/fuel mixture. While many spark plugs are compatible with a range of Hemi engine types, several engines are suited for specific spark plugs.

The optimum gap between the electrodes in the 5.7 Hemi engine is 0.43 inches.

2. Check the Electrode Material

Electrodes need to be durable enough to withstand high temperatures produced during combustion. Platinum or iridium electrodes are usually used in racing applications since they can handle higher temperatures than other metals.

3. Check the Electrode Length

The length of the electrodes is another factor that affects performance. More extended electrodes transfer more energy into the ignition process and produce more power. Short electrodes may not provide sufficient heat to ignite the air/fuel mixture properly.

4. Replacement Ease 

If you replace the faulty spark plug for 5.7 Hemi with its original spark plug, the replacement process will be easy. The complex installation and mechanism of replacing the spark plug can be eased by choosing an exact branded replacement.

Hence look for the spark plugs designed explicitly for 5.7 Hemi for a specific model.

5. Size of the Spark Plug

Thread size is a significant consideration in choosing the spark plug. If the thread is too long or too short, it will not sit properly in the cylinder. The deposition of carbons due to the short height of the spark plug can also lead to holes in them.

The most appropriate thread sizes for 5.7 Hemi are 10mm, 18mm, 14mm, 12 mm, and 16mm. The mismatch of thread size restricts the ignition ability of the spark plug.

What are the different types of Spark Plug?

Here are the different materials used for Spark Plugs that are appropriate for 5.7 Hemi:

Iridium Spark Plug

Iridium spark plugs are made from platinum alloy, which allows the spark to jump across a greater distance. It is suitable for use on vehicles with higher compression ratios. They have a longer life span and are less likely to cause preignition problems.

Platinum Spark Plug

Platinum spark plugs are known for their durability and resistance to corrosion. They are available in both wet and dry designs. They are best suited for use on vehicles with lower compression ratios.

Copper Spark Plug

Copper spark plugs are the least expensive type of spark plugs. They are suitable for use on older cars and those with low mileage. They do not last as long as other types of spark plugs.

How Many Spark Plugs Are in the RAM 2500 Hemi 5.7?

As there are 2 spark plugs required for each cylinder and there is 8 cylinder in Hemi 5.7, the total number of spark plugs is 16. The estimated cost of replacing each spark plug for Hemi 5.7 is $175 to $ 220.


Spark Plugs are one of the most vital parts of your vehicle. A spark plug failure can lead to severe damage to your engine. Hence, choosing the correct spark plug for your 5.7 Hemi Engine is essential to maintain its everlasting efficiency.

Website | + posts

My Name is Christopher Angels, and I am a postgraduate in mechanical engineering. Cars have always excited me as a child, and soon I decided to dive into the world of cars by pursuing mechanical engineering. I also worked as a Mechanic for over 3 years to understand Cars' anatomy and how each part contributes to its working.

Leave a Comment