Basically 2 schools of thought,
One, that flooding the valve train, and springs removes heat and less likely to burn a pivot point on rocker arms, and keeping the springs covered removes heat that lessens spring life.
Two, that too much oil in the upper end with marginal drain back from the restricted aftermarket heads can cause oil pump starvation leading to bottom end failure due to oil starvation, and aeration of the oil.
My own preference, is to keep oil in the pan as much of the time as possible. If I were to use aftermarket heads, I would look into exterior oil drains plumbed from the heads to the pan. It also might lessen windage/aeration, keeping some of the oil out of the valley that would return outside of the valley. Keeping oil off the spinning crank is always a good thing.
You have to deduce which line of reasoning you think will have a better outcome.....
