Thanks what vehicles have the gen 4 ls and are you saying that I would just need the engine and trannyLots of places to start depending on what year LS you use
You'll need the trans from the donor vehicle or you'll have to swap out the bell housing and input shaft on your trans and maybe the pump(auto only). If you have a 5 sp manual trans then you'll need the LS adaptor. If your truck is 4wd it can get more complicated
Motor mounts and possibly 2009-2012 factory V8 or custom power steering and AC lines
Easiest would be to find LH8 or LH9 5.3L out of a factory v8 2009-2012 Colorado/canyon or one from a 2008-2010 H3 alpha.
Next easiest would be any Gen 4 LS... it would work with the 2011 factory pcm
Look up Current Performance wiring... they have a lot of LS swap parts for the 2004-2012 Colorado/canyon and can give you advice