As mentioned, the 6.4 intake (for cars, I don't know about the truck variant) has an imbalance from one bank to the other, even without forced induction, and made worse with forced induction. The factory tune accounts for that for those cylinders.

The 5.7 Eagle car intake does not have the variable runner setup, the 5.7 Eagle truck intake does.

Some posts regarding it: On The Dyno, A Study Of The Effect Of Boost On The 6.4 Intake

Last edited by StricNine; 12/15/14 01:21 PM.
StricNine

79 Li'l Red Express, 15.04 @ 89.57
09 Challenger R/T, 11.95 @ 115.92