A puff of smoke usually means a bad piston ring(s). But its not always the case our cars have a lot of little weird things about them that drive us nuts dont they? When I go WOT w my car my friends say there is always a dark clud of smoke that comes out of my pipes. Come to find out, it mostly happens when my heat is turned to on at the track.
On a further note, I work for Ford Motor Co, and to ease your mind a little when I was in Detroit working, I spoke to an engeneer that was on the DOHC program and he said its a common thing with these motors. He was also familiar with the new ls1's and he said they r the same way, they like to burn a little oil its normal for them. Hope this helps, I would still get it checked out.