YES YOU can i removed both heads on my 99 5.4 f150 to replace the head gaskets/(replace a warped head leaking oil down the back of the engine), its tight in a few places but possible.
according to the ford servvice manual you are suppose to pull the cab(make the job quicker an easier)
but took me 2 1/2(3 the first time) days by myself(no help) to pull the heads from start to finish and 8-9hrs straight work days you need new head bolts, as they are torque to yield bolts, and mutiple extensions and pivot(u-joint) socket extensions, and white out
common practice on 5.4 f150/expiditions(write ups on how to lift cab)
but as said ive done it without lifting the body and its a PITA. but i hear its 20x easier to lift the cab
if you pm me your email i think i can copy the factory service manual and email it to you(its like 20-30 pages and step by step.
the Crank need to be at a certain clock position, you need whiteout to mark the crank and timing chains, and cam gears, if you got any questions let me know, ive done the job twice.
btw the factory manual(after 98) says to remove the engine(or cab) so you dont damage the head surface reinstalling it, the head is a very soft aluminum. i have 96-02 on my computer for ford