Used Diamond W2 Aluminum Heads Yay or Nay?

@Wyrmrider
When I spec’d out oil thru pushrods to Smith Bros the rep recommended against them stating they had seen cups burnt due to oil being forced back down into the pushrod.
I planned on running both oil thru and lightly restricted shaft oiling to my HS rockers.
I went with no oil thru because they do this for a living....
I myself have never burned up anything with too much oil, but I guess if it were flowing past too fast to carry away heat it might be possible... care to elaborate?