As far as I know there is no 6.0 in the 04 GTOs only 5.7L. It wasn't until 05 or 06 that they started the LS2 in the GTO.Hi guys new to the nation. I got a 2005 Colorado. I'm looking an 04 6.0L gto motor. I was wondering if this would be a compatible engine. If so what all do I need to complete the swap. Any info would help a lot thanks.