{"product_id":"drag-specialties-e18-6660sds-spark-plugs-for-1957-1978-harley-davidson-xl-models","title":"Drag Specialties E18-6660SDS Spark Plugs for 1957–1978 Harley-Davidson XL Models","description":"Spark Plugs - '57-'78 XL\n\u003cp\u003eUpgrade the ignition performance of compatible 1957–1978 Harley-Davidson XL models with Drag Specialties E18-6660SDS spark plugs. Designed for dependable service in motorcycle applications, these spark plugs combine a durable construction with materials selected for thermal stability, electrical insulation, and long-term resistance to corrosion. The black ceramic body and red Drag Specialties logo provide a distinctive appearance while maintaining the performance expected from a quality replacement ignition component.\u003c\/p\u003e\u003cp\u003eThe insulator is manufactured from 95% pure alumina for strong resistance to heat shock and superior electrical insulation. Its multi-rib design helps eliminate flashover, supporting consistent spark delivery under demanding operating conditions. A nickel-plated housing resists oxidation and corrosion, while multilayer gaskets and a heat-crimping process provide a leak-free, gas-tight fit when properly installed.\u003c\/p\u003e\u003cp\u003eA copper-core electrode supports efficient electrical and heat conductivity while helping prevent oxidation and corrosion. This construction promotes reliable ignition and extended spark plug service life. Drag Specialties part number E18-6660SDS is intended for fitment on select 1957–1978 Harley-Davidson XL models; verify the motorcycle’s original equipment specifications, engine configuration, and required heat range before installation. Professional installation and correct tightening torque are recommended for the best results.\u003c\/p\u003e\u003cp\u003e\u003cb\u003eFeatures:\u003c\/b\u003e\u003c\/p\u003e\u003cul\u003e\n\u003cli\u003eFitment: Designed for select 1957–1978 Harley-Davidson XL models\u003c\/li\u003e\n\u003cli\u003eBrand: Drag Specialties\u003c\/li\u003e\n\u003cli\u003ePart Number: E18-6660SDS\u003c\/li\u003e\n\u003cli\u003eCeramic Insulator: 95% pure alumina construction provides strong heat-shock resistance and superior insulation\u003c\/li\u003e\n\u003cli\u003eMulti-Rib Design: Helps eliminate flashover for consistent ignition performance\u003c\/li\u003e\n\u003cli\u003eHousing: Nickel-plated construction resists oxidation and corrosion\u003c\/li\u003e\n\u003cli\u003eSealing: Multilayer gaskets and heat-crimping process help create a leak-free, gas-tight fit\u003c\/li\u003e\n\u003cli\u003eElectrode: Copper-core design provides effective electrical and heat conductivity\u003c\/li\u003e\n\u003cli\u003eAppearance: Black ceramic body with a bold red Drag Specialties logo and script\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"DRAG SPECIALTIES","offers":[{"title":"Default Title","offer_id":67569458184427,"sku":"21030206","price":14.79,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0611\/3882\/9547\/files\/9149.png?v=1790805932","url":"https:\/\/ctracingservices.com\/products\/drag-specialties-e18-6660sds-spark-plugs-for-1957-1978-harley-davidson-xl-models","provider":"Cascade Tire \u0026 Racing Services","version":"1.0","type":"link"}