My 340 bare block

yellow rose :
If you are going to do any oil mods, spend you time and money on the inlet side of the pump. Unless you are turning 8K plus, that stuff after the pump is just busy work.

Work on the inlet side of the pump. That’s were the restriction is, and it’s the best bang for your buck.

Thank you for the insight above .
As far as what you're seeing in the photo there I am not sure . there is a pool of oil around the lifter bores and between. I painted some 140 weight for protection. Apparently they used a die grinder with a ball carbide and outlined below the lifter bore opening and between the lifter bores. And I no longer have any idea who "they" are or were. Laughing out loud.