[Adger Smith]

Restricting the lifter galley oil is a practice carried over from the "old" days.
It is not done at my shop any more. 30 years ago, yes! What the previous post (Reed) pointed out is a good explanation. The things that made restricting necessary in the old days have been vastly improved by modern technology. Now, other places in the engine need the oil more than the bottom end did in the "Old days". That last statement means the valve gear needs the oil to live longer.