my thoughts on a 4v 5.4 are it just isnt worth it. It would be nice to get the 6 sp tranny that goes with it, but if you take your 3v, add cnc heads
http://www.livernoismotorsports.com/...Cylinder+Heads, a decent set of cams, and then a whipple, you will make 5-600hp.
just a fyi, the 2v, 3v, and 4v engines all have interchangeable parts within their respective families.