I am just wondering. Turbo cams have minimal valve overlap for full on burns....therefore I would think that they would have less issues of emissions failures......Just wondering if I am thinking in the correct direction of am I totally off.

 

The increase in valve overlap will dilute the incoming fuel mixture as well as allow some of that charge to be sucked out of the exhuast side. At low RPM the overlap is the main reason for higher emissions. That's why high overlap cams make the engine 'chug' at idle speeds that are too low to allow the rich mixture to burn properly....