SPARK PLUG ADAPTERS (pair) for adapting 1955 & earlier Harley Heads with 18mm Spark Plug Hole to use common 14mm Spark Plugs Steel Adapters will work on most early vintage motors 18mm Thread Length - 5/8" 7/8" Hex
SPARK PLUG ADAPTERS (pair) for adapting 1955 & earlier Harley Heads with 18mm Spark Plug Hole to use common 14mm Spark Plugs Steel Adapters will work on most early vintage motors 18mm Thread Length - 5/8" 7/8" Hex