RPM'* shouldn't have dropped. Your RPM'* are going to be the same at a given speed no matter what you do to your engine due to your gear ratio in your tranny and your torque convertor. The only way to change RPM'* at X speed is to change gear ratio or torque convertor. (unless your accelerating because you can change shiftpoints)

But MPG does increase a little with rockers. Goes up a couple MPG. With a cam it goes down 1-3 depending on which cam you get.

Shawn