Macx
Yes, the 5.4L 4 valve is put in Navigators, some Expidition, and some F 250 and bigger. And of course the venrable Lighting. The first thing to go would have to the hood. The 5.4 is much taller and wider that the 4.6. I'm also pretty sure none of the mountings would match up. Its possible, just look at the Cobra R, but practical? You would probably spend almost as much money converting a GT into a 5.4 liter beast as you would buying a Cobra R.
------------------
|