Honestly the rebuild process that I would reccomend wouldn't be the kind of major overhaul with machine work etc. I would suggest just a valve train refresh. Basically 100% of the process can be done with hand tools. A couple small specialty tools will be needed for some specific tasks like removing the pulley or changing the springs. The bottomends on these motors run forever and don't need to be rebuilt the way sbc motors require. A great option would be to find a lower mileage 5.3 (1/3 the price of a 6.0 and much more abundant.) and build it up on an engine stand. A full top end over haul with some go fast goodies would cost about $1200 or a little more with good heads. Again all done by hand giving you seriously more power and reliability. The top ends on these motors isn't great stock so even a mildly rebuilt top end 200k mile 5.3 will be stronger than say a 75k mile stock 6.0, because simply swapping to another stock motor you leave the same weak links, needle bearing rockers, timing chain, lifters, pushrods, etc. A little wrench time and more than likely less money will get you awesome results this route. No need for tons of space or tools it can be done.

 

If I were to go this route, should I try to buy some better stock-type heads (243/317) and slap them on, or try to buy the parts (rocker arms, valves/springs, whatever else goes into it) and find a shop to machine and rebuild the ones I already have?

I'd love to build a motor someday, but I live in an apartment without a garage, and I don't have the space for an engine stand...that would be awesome though if I did.

 

I ordered the flashscan V2 so I can tune and re-tune my truck down the road as the mods keep coming. I hope this might pacify me for the time being until I figure out the best option for what I want the truck to do.

 

If you decide to go the 6.0 route just get a lq4 the 45hp difference vs the lq9 was in the tune. Once correctly tuned the difference is less than 10rwhp and the lq4 should be around $500-1000 cheaper.