Drilling oil galleries and oil return holes?

I understand your rationale IQ - but I have to respectfully disagree. These are street engines. Windage in these cases is not a big deal, and in fact will add to the oil the lobes get. I'd guess it's less of a power loss than a HV oil pump. Not every build needs a 7qt pan, scraper, and covers over the valley holes. In fact the vast majority don't.