Where are the spark plugs located in an 04 F250?

They are located right in between the where intake manifold ends and the valve cover starts. You must remove a 7mm hex head bolt to remove the coil unit, then unplug the wire for the coil unit for each spark plug, remove the coil unit and you need a special very long spark plug socket to go down into the spark plug hole. Beware!!! The 4.6 and 5.4 Ford V-8 engines are known to have the spark plugs break off in the head for no appearent reason whatsoever and without warning.