340 cam help needed

someone makes a chevy liftr with two flats they say HV pump but IDK
some are made so the flat does not go all the way to the bottom of the lifter
only lubes when on the base circle
Our Jag XKE had drilled camshafts with the hole right before the opening ramp
wonder why I never tried that on a ohv motor
should not be that hard to get lube into the center of the cam