Really sounds like you should do some research on intake and plenum design.

Generally Speaking:

* Longer intake passages produce more low end torque. The 3.5 runners are no doubt engineered to specifically match the intake pulses. Similar to a Tuned Port GM intake manifold. High end Hp is sacraficed to provide low rpm torque. Good for passenger cars and trucks that are heavy, or need to get a load moving.

* Shorter intake runners produce more high end HP by reducing turbulance, and increasing flow. ie a single plane manifold in a carb application, or individual throttle bodys on an EFI spp..... basically race car stuff that needs super high end HP, and can sacrafice all the low end torque.


Whoever designed that intake system was an engineer, and did not put anything in there they thought would decrease performance, be it HP, Torque, Noise.... I'm not an engineer either, so I usually try to make small changes, and do a crap ton of research to find out how I am changing the whole picture.

I will go look around, and find you some Intake research stuff, and you can go from there.