I have a 2007 sierra w/4.8L V8 and i was just wondering what are the differences between this engine and the 5.3L? Is it the same block just a small bore? or shorter stroke? just trying to figure out which parts are compatible with each other. and what parts i could maybe take off the 5.3 and slap on my 4.8 for an upgrade. any info is appreciated...thanks!