Lift and Duration are the two parameters of interest in cam design along
with the ramp geometry.

Lift is how far the cam pushes the valve open.  Measured in inches.

Duration is how long the cam keeps the valve open.  Measured in degrees.

Overlap is the degree (Degrees/360) of total rotation where both the intake
and the exhaust valves are open at the same time.

The ramp geometry determines the acceleration of the valve and valve train
as it is pushed up by the cam lobe.  This attribute helps to determine the
rpm at which valve 'float' occurs.  When the valve cannot follow the
oscillation of the cam lobe it is said to 'float'

Why don't 2 stroke engines have valve float? (NVC).

Al (some cats are two stroke)