I have a 2005 Suburban with the 5.3 Liter FlexFuel Engine. Question is If I buy a 2005 GTO LS2 Engine outside of PCM Programming what are my main issues going to be? can I just bolt on belt driven accessories and plug in same connectors?

 

Probably, but I don't know for sure.

Back in college we put a carbed 383 that that was originally a 350 from a 1975 pickup in place of a TPI 305 on my roomate's 1991 GTA Trans Am. We were lucky and all the brackets bolted up perfectly and we enjoyed factory A/C, alternator and power steering, even though I think the block deck heights were different. All the "holes" lined up and it was quite painless as far as engine swaps go (other than getting the stupid bolts through the mounts which thwarted us for about 4 hours).

Of course those were gen I SBC's... but from what I understand the 5.3 is an LS motor with a steel block so I would guess things would match, but I don't know for sure.