this article has my head spinning wanting to do this to my 2003 Silverado that i bought a week ago.

Its a 5.3L and for a stock ext cab she runs pretty good, over 80 when it shifts out of 2nd gear, but there is always room for more.

Im, gonna cut off the stock muffler and weld in a 2.5 in/out Dynomax Ultra flow welded muffler i have new in the box in the garage, and get the volant CAI, but first i want to have the truck dynoed bone stock to see where im starting. I also bought a stock 07 rad and efan setup im gonna swap in to ditch the stock clutch fan setup, along with a 170 deg t-stat.

Hey Allen,

Quick question for you, on a completely bone stock 03 5.3, what kind of power can be had with just the tune? Also how much better can you get the MPG with just a tune and a few small bolt on mods, like i have listed above?

Thanks