if you like the four doors, your better off buying a four door that had a v8 from factory. also, the front dress on a explorer is shorter then a older vic, and or mustang and f150. you would also have to either change the P.A.T.S. over, or have it programed out.
however, if your still wanting to do this, you would be better off finding a v8 explorer donor truck that is the same year.
here is your shopping list.
trans
motor
transfer case
drive shafts
rad/condenser ***update, 4L SOHC rad/condenser will work***
a/c lines
power steering lines, and cooler
motor harness, and wiring from alt to battery ***update, 4L underhood body harness will mate to 5L motor harness, however, oil gauge wire, and a/c wires need to be modified to work***
throttle cable
trans shifter cable (not sure if i will need it, but hey) ***update, 5r55e cable will work***
air filter box ***update 4L SOHC box, and sensor will work***
exhaust from manifolds to muffler
fuel pump (not sure if needed but.....) ***update, 4L SOHC pump will work***
g.e.m.
p.a.t.s.
key ring around ignition cylinder, and ignition cylinder
locks including hatch lock
radio bezel
computer
cruise motor with cable
evap lines
if you want more info, start around page 9 of my registry. i have a sport, but its pretty much the same deal.