I have a 2004 4.6 4x4, if I do a full exhaust (headers back) and a tuner will the gains be noticable? Im talking mpg and seat of pants. Any input is appreciated, thanks.

-Jesse

 

Yeah. Different setups will see different numbers but headers and a tune will see gains.

 

Yes there will be a noticeable difference but not drastically so. Increasing MPG is damn near impossible w/o decreasing weight. The idea is to gain HP/TQ and not use more gas doing it. Keep in mind with a full exhaust and tunes that little pedal to the right may get used a little more ..so dont worry about mpg's and just have fun