I wouldn't be too worried. (that's easy for me to say, right!) You're into this truck six figures, which makes this a BIG disappointment. However, you're not the only one that has had this issue. Ford will get it figured out, they have to. Looking on the bright side of the situation, you know that the first owner (like everyone) had to take the original engine out for a rip and tear session. The replacement engine likely doesn't have this use/abuse and you're starting out with a new engine that you will use and maintain your way. You're enduring some labor pains, but none the less, you are living "the dream" my friend.