I have a 2004 excursion 4x4 with a 5.4 2v. How can I get more power below 4k rpm? Right now I have a diablo 91 oct tune and the restrictors removed from the exhaust.

 

You have 2 choices. More torque production from the engine, or multiply the available torque to the ground.
To get more from the engine will require forced induction via a supercharger or turbocharger. To put more to the ground will mean a gear change. I'd say 4.10 at the minimum, or even 4.30 or 4.56 for best results. I'd bet your Ex has a 3.73 in it now, so the fuel mileage losses will be negligible, if you even lose at all.
JL

 

I think I have a 4:10, Best gas mileage is at 70mph about 2250rpm.
I guess My only choice is a lightning supercharger setup from the early 2000's lightning. Definetly not going with a centrifugal blower. I have a procharger on my mustang and power below 3k is the same as n/a.

 

4.56 gears will help as mentioned. Opening up the exhaust actually will move the powerband up and cost a little torque.

 

I know this sounds stupid, but there are 2 holes in your intake reservoir under where the filter is. get a good filter, like a k&n and use some gorilla tape (cause its black) and tape over those holes. i know its stupid but it actually helped my Super Duty.

 

You're the first person I've read that has mentioned those two holes! What the heck are the there for anyway? I figured they were maybe for an easy way to inspect the filter for condition (cleanliness).