I agree with mattr762. The 4.6 isn't even in the same league as the Chevy motor (and it hurts like hell to say that being a die hard Ford man). Less mpg, less hp. Even the 5.4 needs a blower to come close in hp. Why Ford, why <sobbing>?!?!?!?!
Check out the Ford Australia site. They have mid and full size rwd cars with IRS, but we don't. They have a Falcon GT (the mid size rwd) from their FPV (Ford Performance Vehicles, their version of SVT) with a 5.4 32 valver making 290kw which if I figured it right is just about 390 hp.........naturally aspirated!!! That's better then our supercharged Lightning.