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NGK
Iridium IX Spark Plugs (HEMI 16-pack)
SKU: 6509-LTR6IX-11
Estimated Install Cost
Total with part: $175–$330
What You'll Need
Spark plug socket, torque wrench, anti-seize compound.
Great entry-level mod for any build
Compatible Vehicles
Fits all 5.7L and 6.4L dual-plug HEMI. Stock heat range — for NA or lightly modded engines.
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Tip: Search for "6509-LTR6IX-11" to find the exact product. Prices may vary by retailer.
Why Install This?
Benefits
- More reliable combustion under high load and boost
- Longer service life compared to stock plugs, especially with forced induction
- Easy bolt-on installation — most people can do this in their driveway with basic tools
What Does This Do?
The HEMI's dual-plug design means you need 16 spark plugs instead of the usual 8. NGK's Iridium IX plugs use an ultra-fine iridium center electrode that requires less voltage to fire, produces a more focused spark, and lasts significantly longer than copper plugs. The stock heat range (IX) is perfect for naturally aspirated engines — even with bolt-on mods like intakes and exhausts. If you're adding forced induction (supercharger/turbo), you'll want a colder heat range to prevent pre-ignition under the higher combustion temperatures. These are the go-to replacement plugs for most HEMI owners.
Fitment Notes
Fits all 5.7L and 6.4L dual-plug HEMI. Stock heat range — for NA or lightly modded engines.
Technical Details
Premium iridium plugs for dual-plug HEMI. Full 16-pack. Stock heat range.
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