[C15_Sierra]

Definitely worth the time, and yes LS parts swap across the whole range. A friend of mine in TX took a 5.3 with a bad oil pump that he got for $100, bored out the cylinders to a 5.7 (the 5.3 shares the same crank as the LS1), bolted up some Z06 heads and cam, and got himself a nice iron-block LS6 for around $1000 into the setup. Not bad bang for buck.

Me, I'm just trundling along with a stock 5.3, albeit 2WD. I haven't had any clearance problems with any of the mounting or headers, and I'm on the stock oil pan. But since I'm 2WD I'm not sure if that translates over into 4x4 world, since there's a lot more going on. I'm sure there's plenty of documented 4WD setups, I've seen a bunch of Jeep guys running 5.3's, so there is a setup that should fit your K10.

Wiring/programming the computer is a breeze. Plenty of info up on LS1TECH and around the 'net on that end. I love how GM essentially turned these into crate motors when the cars turn to dust.

Have fun!