After delving into the grey matter of what's left of my brain, I have come to the conclusion that it probably really does not matter what the size of the hole in the lifter disc might be unless it is smaller in diameter than the hole in the cupped ends of the push rod. The reason being is that the smallest hole or orifice in the lifter/pushrod/rocker arm is what is going to dictate the flow/pressure of this oiling circuit. If I remember correctly (big if) the smallest hole or orifice is the pee hole in the pushrod socket of the rocker arm that piddles oil on the rocker ball and indirectly down to the valve guide area. Please correct me if this isn not the smallest orifice. SOOOO, if all of the internal lifter pieces are similar in both of the lifters that the original OP compared, disc hole diameter size is probably a moot point.
Thanks, Royce for the good discussion and for FORCING me to think.
Frank
Thanks, Royce for the good discussion and for FORCING me to think.
Frank