[trentkoger]

I have an '04 silverado 1500 with a 5.3. I am wanting to upgrade to an LS2 or LS3, has anyone else done this? Any ideas on the easiest ways to go about this would be appreciated.

 

[redvett]

Without new wiring harness and PCM and a custom tune you cannot use the LS2 or LS3 since they run on different operating systems. Your best bet is to get a 6.0L out of a wreck and have your PCM custom tuned.

 

[RayVoy]

Pick up a matching transmission and rear end as well, the 5.3 versions are not strong enough.