Does the Nissan and "Hemi" have 4-valves a cylinder? I thought a read somewhere in a Ford artical that they stayed away from 4-valve Heads partly because they didn't want to sacrifice too much low-end power? And of course they wanted to avoid more moveing parts (additional cams). Heck Ford seems to confident in this new 3-valver that they put it in the new Mustangs and even the 6.8 V-10. Also dumping Lincolns 4-valver in favor of the new 3-valve. Anyways I think there are several other things they can do to improve the power output. For instance i changed the oil in my dads '04 5.4. I was disgusted by the tiny diameter exhaust tubeing which was later comfirmed to be 2.5". My 2.0L Focus has a 2.5" exhaust...aftermarket but cmon! My Focus went from 2.0" to 2.5" and lost minimal low end and only gained massive amounts of mindrange to top end. I also agrea that a good 5-speed or even 6-speed could help ALOT. The 300hp Lincoln Aviator has a 5-speed auto. And now the Superdutys have a 5-speed auto for gassers and Diesel alike. I think the new style F-150's biggest downfall is the tranny....or lack there of. Also for the 5.3L. My step brother had a 2001 Z71 with 5.3. Custom cat-back and K&N FIPK. I was amazed at how sluggish it was. Worse so than the new 5.4's.