has anyone really done a performance build on a 300 I6? my plan is port & polish, cam,pistons,intake,msd ignition, has anyone done this? if so how much more power does it really make and how much is the mpg affected?

 

You might want to read through some of the posts on the dedicated inline six cylinder forum further down the main page: Ford Inline Six, 200, 250, 4.9L / 300 - Ford Truck Enthusiasts Forums