You don't "need" a taller hood. You can cut your stock hood and fit the Intake through like an old school hotrod. Plenty of people do it this way.
Also, since mustang hoods are fiberglass, you can glass a scoop onto your stock hood. This is the route I will go if I go with the 5.4.
I have actually quite possibly found a killer deal on a 4.6 DOHC from an aviator. 60k miles, super-clean and only 600$!
Imma jump on this one if its legit. Save me some money so I can buy a 240sx for a DD and drift car.
Also, since my last post, I have designed a system to allow the keeping of the IMRC plates on the DOHC engines (Mark VIII, Navi, Aviator, Cobra, etc,etc.). You either have to remove the IMRC's or get a DOHC computer and harness to open and close them. My design opens them at a preset RPM via an rpm switch and servo system. Most people opt to take them out, but I have been chatting with the guys down at Sullivan and another friend that has cornered the carburated 4.6 DOHC market over the last few months and have come up with a solution. I may start manufacturing and selling said plates here on the forum (with appropriate permissions granted of course). More to come on this subject later
Anyhow, Ill keep my progress posted!