[stuartb]

olddog
I have heard that the 4.6 will fit but you might have to modify the engine bay a little bit. But you are right about the carb vs. efi, the carb will be easier and less $$$ to work on. But you won't have the efi and the gas mileage sounds pretty good to me, remember that your putting it in a cobra and unless this is going to be a daily driver it is a fun toy.
Also go to shop talk and look for the thead trying to decide on engine there is a diagram about half way down on the page that shows the differences in the size of the engines as far as height and width go. BTW, most of what I am writing I got off of this site from other users when I was trying to decide.

Take a look at engine factory they have efi 351w with 425hp.