It's common for that to happen at start up and the reason is the crappy PCV system that dumps a lot of oil into the upper intake on the drivers side and the throttle body gets oil vapor from the valve cover tube on the other bank. When I built my motor at 59K the upper plenum was coated in about a half quart of oil, that in turns finds its way into the combustion chamber which lowers octane and could cause detonation and the smoking out your the tailpipes at start up! Go with K&N breathers my fellow SVT'ers!