Other way round, Too much duration and the valve will be open longer, piston will go way down out the way of even 10+mm lift cams. But sometimes if you open too much you loose intake velocity and thats a whole other game haha I dont even know the beginnings of it all but theres loads to look at with high powered n/a, from combustion chamber shape, to piston spec and squish gap in chamber to cam specs and trumpet lengths blah blah blah haha