I'm a novice at this and hopefully others who've done the swap will jump in, but-- I have an 03 Tahoe, which is dbw, had the 4.8, found an almost complete 6.0 from an 05 2wd Silverado, also dbw. Everything is the same for the 4.8, 5.3 and 6.0 externally like valve covers, oil pans, intakes, throttle bodies, alternators etc. I did have to swap one of the valve covers because the pcv system was a little different between the 2. There's 2 different 6.0's, the LQ4 and the LQ9. The LQ9 came in the Escalade, has the domed pistons, LQ4 came in Silverado and others-- can't remember. You can use the 5.3 intake and the throttle body to keep the dbc setup. Remember, all the components are the same for the 4.8, 5.3 and 6.0, so no problem there. Internally they're different. You can run the 6.0 with the 5.3 tune but me and a bunch of other members would recommend getting it tuned. Majority of guys like black bear tuning. They have in person tuning and the autocal, which let's you get tunes via email. Everyone has a personal preference on what year motor they like. Some have some good points, other not so much. So you'd have to do your homework with that. Once you find the motor you want , and get it, you're gonna want to do a few other little upgrades, cam, torque converter, heads, whatever. Believe me, it will get out of hand! Lol, we've all been there or on our way there. So whatever you decide to do make sure you have a nice budget. Cost me over $7700 for my swap, and I'm still not done! I know I jumped around a lot and I might've skipped a few things, but this is the jist of it. Any other questions please don't hesitate to ask. I know a few other guys will jump in to help you out. Around here we love helping guys spend money on mods!! All good ones tho.
