48-65 Panhead, 66-74 FL Shovel, 71-74 FX Shovel, 54-78 Sportster, 56-73 Servi Car
Spark Plugs including a wider-base insulator which provides an easier path to speed the transfer of heat and a longer insulator nose containing a center electrode of pure copper inside of chrome-nickel to transfer heat between firings and help resist fouling.