1 to1 cam
When the piston reaches bottom dead center, the air stream will still continue moving into the cylinder due to the momentum of the mass of the charge.Even though the piston has passed BDC and is now moving ABDC (back towards TDC, in other words), the air is compressing upon itself, and is able to move into the cylinder because the intake valve is still open.
On the other hand, it's equally as foolish to install a short cam into a motor with a fairly high static compression ratio.
The reason closing the intake valve ABDC works to make more power is because air is a gas, and as such is compressible (unlike liquids or solids).
When air enters the engine it does so at a relatively high velocity.
This info was taken from Crane Cams and is valid information for fellows who know nothing at all about choosing a cam, and that includes most of the fellows who come on this forum asking questions.
Sometimes it's difficult trying to explain to fellows who are new to hot rodding that you have to match the characteristics of the camshaft to the static compression ratio of the motor along with the operating range where the cam makes power. It must be coordinated with other motor and drivetrain parts in order to arrive at a combination of parts that will all work together toward a common goal.It might lope, but it will lack the power to pull the hat off your head.