iv got an 03 gmc sierra 1500 z71. im thinking my current 5.3 is on its way out. its knocking upon start up and burns oil during hard down shifts and its only got 101k on it:neutral:. i would like to get a junkyard 5.3 from an 05-07 truck that made 20+ more hp stock, with low miles and swap it out. im wondering if it would directly fit, wire harness computer accesories etc? the 05-07 also have e fans could i use my mechinical one instead? i would like to make around low 400 hp by doing a very mild cam swap should i change the bearings too? does anyone have any ideas of how mild to go without absoultly killing my mpg i would just like to open it up a little bit. i would also like to do short tube headers and maybe an intake manifold. i am trying to do this on a budget so i am open to suggesitions and any information.