I thought ford corvered this even if it was out of warrenty. The did on my 2000 lightning when it blew a spark plug out of the head. It was over in miles for warrenty but ford was all hush hush about it then and just replaced the entire head.
If I remember right ford changed the spark plug to one with more threads to help solve this problem.

Thats pretty smart of John to just pull the body though. Way easier to work on that way. Think he should get extra paid hours for coming up with that.