Ignition Coil & Iridium Spark Plugs for Chrysler 300 (2005) 5.7L V8

High-Output Ignition Coil & Iridium Spark Plugs for Chrysler 300

Upgrades the factory ignition system to deliver higher voltage and stronger spark energy, curing misfires and rough idling in the 5.7L HEMI.

The Stock 300 Ignition System Weaknesses

The OEM ignition setup on the early LX-chassis 5.7L HEMI is notorious for voltage degradation and thermal breakdown over time. Factory coils suffer from heat soak generated by the cast iron block and aluminum heads, which drastically increases internal coil resistance. This resistance leads to weaker spark energy, causing incomplete combustion, rough idle, increased fuel consumption, and inevitable engine misfires. Furthermore, standard factory plugs erode rapidly under these harsh thermal conditions, widening the spark gap beyond optimal specifications and triggering a check engine light (CEL) under load or hard acceleration.

The Engineering Solution

This comprehensive ignition overhaul directly addresses thermal and electrical deficiencies by utilizing enhanced-winding ignition coils and premium iridium spark plugs. The upgraded coils feature improved primary and secondary copper windings, insulated with high-dielectric epoxy to resist heat soak and prevent voltage leakage. This is designed to ensure a stable, high-energy voltage supply to the unique dual-plug HEMI combustion chambers. Paired with iridium-tipped spark plugs—which boast an exceptionally high melting point and superior electrode shape retention—the system maintains precise gap tolerances over an extended service life. The hotter spark efficiently burns off carbon deposits, eliminating fouling and ensuring peak combustion efficiency across the entire RPM range.

Technical Specifications

Compatibility

• 2005 Chrysler 300 5.7L V8

The Chrysler Muscle Standard

Designed to support the heavy low-end torque and horsepower demands of the modern American muscle platform, this direct-replacement ignition kit restores lost power and ensures reliable, misfire-free performance under heavy throttle.

Common Questions

Will this ignition coil and spark plug kit fit my 2005 Chrysler 300 5.7L HEMI?
Yes, this kit is a direct replacement made specifically for the 2005 Chrysler 300 equipped with the 5.7L HEMI V8 (EZB engine code on the LX chassis).

Does this kit fit a 2006 or newer Chrysler 300 5.7L V8 or the V6 models?
This kit is built specifically for the 2005 Chrysler 300 5.7L V8, which uses the early UF378 / 56028394AB style ignition system.

What OEM and aftermarket part numbers does this kit replace?
This package cross-references with part numbers UF378, 5C1409, 56028394AB, C1414, UF505, 6987, and ZFR6F-11G.

How does this upgrade improve on the factory 5.7L HEMI ignition setup?
The coils use enhanced primary and secondary copper windings insulated with high-dielectric epoxy to resist heat soak and voltage leakage, while the iridium-tipped spark plugs maintain precise gap tolerances for consistent spark energy in the dual-plug HEMI combustion chambers.

Are modifications required for installation?
The coils and iridium spark plugs are direct-replacement components engineered to fit the factory 2005 5.7L HEMI dual-plug cylinder heads without modification.