The first time the plug blew out (2011 CVPI, 4.6L V8), I repaired with a heli-coil, which lasted about a year, then blew out again. The Cal-Van insert system is not only easier to install, but I expect the repair to be permanent this time. Well worth the added expense.The reason I rated the instructions at 4 stars is because they are so small, I could hardly read them or see the pictures. There are excellent videos on YouTube that show how to install the inserts. FordTechMakuloco is highly recommended.
Rating: [5 of 5 Stars!]