2000 6.0 engine swap

I have a 2000 2500 truck with the 6.0 engine. I recently picked up a 2004 LQ4 engine with 50k miles for a good price. Will this newer engine be a direct bolt in for my 2000 truck?

After swapping intakes,yes.

I need to swap the entire intake, or just switch throttle bodies?

I think your old intake will have the egr port open and the new manifolds wont have the egr valve. You can buy the block off plate from gm, its cheap. That and the throttle body. I would assume everything else would bolt up. You might have an issue with returnless vs non return fuel system? And the knock sensors may or may not play nice with the old operating system in the 2000 pcm. They also might have different size injectors and there for require a different fuel map. Ive also heard about the alternators on the older trucks not playing nice with the newer operating systems and vice versa. I programmed an 02 operating system into my 99 for a few hours as an experiment and the battery light blinked the entire time. Others will have more detailed info. Just giving you some things too think about and look out for.

I did the same swap just over a year ago, I used the LQ4 intake since it was already on the engine I actually did install the egr, the port was there just needed to be machined out, I was able to remove the threaded inserts from the old intake and installed them in the new one as it already had the recesses for them. it may be more work than changing the intake, but it only took me about an hour total including swapping the DBW throttle body to my original DBC. If I had to do it again I would do it the same way.

As for the programing I would guess you will reuse the 2000 alternator if not you may find an issue there, I don't believe the 04 LQ4 had an option for a returnless fuel system but I have been mistaken before. As far as injectors go they are different part numbers however I compared fuel maps and pulse width based on mass air/engine load and they are so close to identical that I can't imagine you will have any problem using the new intake and injectors just as long as you swap throttle bodies and deal with the EGR issue.

Thanks Db, just what I needed to know. Sounds like a pretty straightforward swap.