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Decent.
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Prices may varyThis product ranks #31 of 33 in Spark Plug.Three above it ↓
Last reviewed June 1, 2026
TL;DR Copper center electrode for older Dodge/Chrysler V8 and small engines (Briggs and Stratton, Kohler, marine); no service interval or heat range stated on the product page. Pre-gapped to spec per reports, and well-reviewed by owners.
Copper center electrode, standard J-gap, 14mm thread, gasket seat. RC12YC covers older Dodge and Chrysler V8 engines (318, 360 cubic inch), Briggs and Stratton, Kohler, and select marine outboards. Heat range, factory gap, and mileage interval are not stated on the product page. Owners report correct fit across the listed applications, and note the plugs arrive pre-gapped to spec. No widespread cross-reference or misfire complaints in the sample.
Right pick for an older Dodge/Chrysler V8, Briggs and Stratton or Kohler small engine, or marine outboard OEM-specified for the RC12YC. Skip if your engine is OEM-specified for platinum or iridium, where a longer-life electrode material matches the required service interval.
No chemical exposure pathway: the RC12YC is a passive ignition-system replacement part with no SDS. Copper center electrode has zero precious-metal extraction footprint. Steel shell is recyclable as ferrous scrap; ceramic insulator goes to landfill. No manufacturer take-back program exists as of 2026.
The Amazon listing for Champion RC12YC Copper Plus Spark Plug (4-Pack) carries a California Prop 65 warning. California requires this warning on a very wide range of manufactured goods — including rubber, vinyl, plastic, and metal automotive parts — whenever trace exposure to any of roughly 900 listed substances (commonly phthalates or heavy metals) is possible, regardless of whether the specific product poses a meaningful health risk. As a passive accessory, Champion RC12YC Copper Plus Spark Plug (4-Pack) has no Safety Data Sheet, so there's no chemistry breakdown to translate beyond that.
Marketing copy from Champion, via Amazon. Not editorial.
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