NGK
Iridium Performance Spark Plugs - Set of 16
SKU: NGK-LZFR5CI-16
View on NGK website+0.3
Pounds Added vs Stock
What You'll Need
Spark plug socket (5/8"), ratchet with extensions, torque wrench, anti-seize. Patience — the rear bank plugs on HEMI engines are notoriously hard to reach.
Great entry-level mod for any build
Compatible Vehicles
Price Comparison
Compare prices across 2 retailers — all links go to the real product page
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?
This is a complete set of 16 iridium spark plugs for the HEMI's unique dual-plug-per-cylinder design (8 cylinders × 2 plugs each). Iridium is harder and more durable than standard copper or platinum, allowing a finer electrode tip for a more concentrated spark. Benefits: significantly longer life than copper plugs (60,000+ miles vs 15,000-20,000), better ignitability means smoother idle and better throttle response, and the fine-wire tip resists fouling. A complete set means all 16 plugs match — mismatched plugs can cause rough running. Trade-offs: at roughly $5-6 per plug × 16, the full set costs about $80-100 — reasonable but more than copper. Iridium plugs are the right choice for stock and mildly modified engines. For heavily boosted builds (supercharger, 10+ PSI), copper plugs are actually preferred because copper dissipates heat faster and you can run a colder heat range. Always gap to your tuner's spec — the factory gap may not be optimal for modified engines.
Technical Details
Iridium IX spark plugs pre-gapped for HEMI engines. Set of 16 for dual-plug heads. Improved ignitability and throttle response. One heat range colder for modified engines.
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