I tried plugging it with a gatorade cap (perfect size), and there was NO difference to my senses. Power, sound or otherwise.

I actually believe it's more of a vacuum equalizing chamber (to smooth out intake pulses) than a resonance chamber.

"Does this part need to be in there?"

1996 Dodge 1500 single cab / short bed, 5.9 4x4; 2" lift (springs not blocks), C.A.I and more mods to come.