"creating higher chamber pressures which would help 'push' the valve closed?"

That would only be the case if valve was "floating" at peak opening, which is also the moment I suspect there is the closest to equal pressure on BOTH sides of the valve, resulting in minimal "push". Can't believe air flow velocity/force on back side of intake valve is a significant factor twocents

As I see it, for example, 2" intake =3.14 Sq in, if cylinder fill was at a vacuum, and intake track at NA atmospheric pressure or zero vacuum, intake back side valve pressure at max would be 3.14x14.7, or close to 50lbs of loss of valve spring closing pressure, and this case will never be incurred, I suspect, and this effect will always be much less. and rpm/load dependent.

Last edited by jcc; 07/25/17 07:00 PM.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.