Thanks 360View! Some good reading there. The descriptions there seem to me like they want a cam ground with wide lobe seperation and then retarding it to keep the exhaust opening/closeing the same, is that how it sounds to you? The late intake closeing will definately bleed some preasure back in the intake. I would guess this forward-backward motion of the mixture around the valve would help atomize the fuel more also and provide some increase in efficency.