"Veeduber" wrote

Factors that effect the RATE
at which the valves open or close is the MASS or weight of the
components in the system, meaning the tappet, push-rod and valve, as
well as the strength of the SPRING, the tension of which must be
overcome in order to OPEN either valve. And of course, if you want
the valve to CLOSE quickly, you will need a stronger spring, but you
must pay for that greater strength upon opening the valve.

-R.S.Hoover

I'm going to go out on a limb here Bob and say that the RATE of valve
opening and closing is a function of RPM and cam lobe contour only. Mass of
the valve train would primarily affect the max RPM attainable without
destructive valve float.
Tom