A centrifugal supercharger wont do much for down low power or torque. It is a very poor choice for a truck. There is a reason why SVT racing & engineering equipped a roots style supercharger on the f150 lightnings.

The amount of airflow a centrifugal delivers (literally blows) increases roughly at a square of its driven speed. It is NOT linear like a roots supercharger.

So say at for example the procharger @ 3k rpm delivers 'X' airflow. At 5.5k it now delivers roughly X^2 airflow. This means that at every point below redline you will NOT be at maximum boost. If your set for 8psi at 5500 rpm. Then you can figure that at 2750 rpm (half SC driven speed) you now have the square root of the boost at 5500 rpm... or a measly 2.3 psi.

Obviously the procharger is the clear winner for power up top, but this is a truck not a race vehicle. The roots is by far the best choice for down low power. Also this is why prochargers have a BOV, because the power creeps up incredibly fast once the engine is revving high.

Since the roots supercharger delivers airflow linearly (like an engine) it will maintain full boost throughout the rev band. In theory you should have full boost at idle but it doesn't actually work that way because of air leakage around the rotors inside the blower when it is turning at very low RPM.

In brevity... do this:

 

Lots of different opinions and arguments here. I appreciate the input. Perhaps, I should maybe contact the guys at SuperSixMotorsports since they deal primarily with Ford V6es and see what they have to say about LTs and shorties. If you really think about it, any engine can go fast with enough imagination and elbow grease. Finding out what works without sacrificing major moolah is every gearhead's fantasy