Calender, but interestingly he was optimistic that it may be rushed sooner. I cant see how it would be, you wouldent believe how long it takes to bring something to market, but GM has been reacting faster then it ever has in the past, and he was convinced that it was comming for the next model year (08). It kind of makes sense, as if they are waiting for an H2 engine upgrade so they can maintain its position, but that is not him talking, that is me speculating so who knows what GM is thinking. Consider what they do with the Yukon Denali and the Escalade. The escalade is supposed to be top of the luxery gm pack, so the Denali is detuned (and it actualy is if you look at the dyno plot see link). It is all in the name of maintaining a dominant package to discourage overcompetion between brands, I see no reason they wouldent do it within a brand. But thats just speculation and all that matters is fact.
http://media.gm.com/us/powertrain/en...07/07truck.htm