The 5.4 has a taller deck height than the 4.6, so that throws off the alightment for the lower intake/supercharger assembly. You could bolt your heads on a 5.4 short block, then bolt on the 5.4 blower.
its funny that people are always looking to swap on a blower from another ford vehilce to get some boost on the cheap. and most dont realise that if your patient you can put a centri on your car for around 2500. hell thats what i did. total cost 2650. it would have been cheaper but i had to buy another maf since the lightning 90mm was jacked up.