the plug hole can be fixed with the head on. i did my f150 5.4. the kit costs $130 but local machine shops charge $100 to repair 1 hole. this is for the f150 which i assume is harder to get to. if you have it repaired at a shop dont use a heli coil. it wont last and wont seal. use an insert. timesert makes a kit for the ford engines. http://www.timesert.com/sprksert.html
oh by the way its a common problem with the triton 5.4 and v10's blowing plugs.