must get the 6.0, don't settle for less. Willing to bet you'll be plagued with the typical GM window regulator problem on coupes. Plenty of interior rattle noise is bound to happen as well. If you plan on making any power, beef up the rear end or you'll probably blow it pm RsvDon. He probably would be the most knowledgeable on this board regarding GTO's as he did a sweet Holden conversion on his if I remember right