Repairs worn, damaged, or striped threads . Can be used with any alloy or cast iron head . Kits to fit M14-1.25 spark plug port threads, gasketed or tapered. Designed for use with almost any engine. No drilling required This is a Fix-A-Thread Plug-Saver Kit designed to specifically repair the spark plug ports in 4.6, 5.4 and 6.8 liter Ford Triton engines. This specially designed M14-1.25 Plug-Saver kit ensures the permanent repair of the spark plug port threads in the Triton engine by providing a mechanically locked solid repair sleeve insert between the threads in the head and the "half-thread" taper seat spark plug.