That would be true if the manufacturer was putting tuned exhaust manifolds on the engines but they don't, and probably never will, since it's not cost effective.I have heard recently that headers aren't worth the money nor the effort to put on the 5.3l anyone else have any input or experience saying otherwise?
Doesn't sound like reliable advice to me. IMOanother forum im on chevytalk.org I havent gotten any bad advice from them yet and on this occasion i was pretty currious they also said that a cold air intake wouldnt do any good either but that sounds like bad info to me
exhaust, low temp thermostat, mass air sensor, lightened pulleys, etc. there are several fairly inexpensive upgrades that make all the difference in the world.I got a 03 silverado 5.3L with cold air intake, programmer, throttle body spacer, what little performance mods can i do?