Mercury - Quicksilver 816761Q10 Spark Plug Wire Kit V8 GM MerCruiser Engines (454 & 482 CID) Points & Thunderbolt Ignition 816761Q10. Overview. When you turn the key, you want instant ignition - not hesitation. The Quicksilver 816761Q10 Spark Plug Wire Kit keeps your classic V8 GM-based MerCruiser engine (454 and 482 CID) firing strong and running smooth. Designed for both conventional points ignition systems (1977-1985) and Thunderbolt systems (1969-1981), this OEM set delivers clean spark and