Drilling oil galleries and oil return holes?

What is the purpose of this engine? How hard are you going to run it that you feel these modifications are even necessary?

I don't "feel" anything. It is the reason I am asking what these mods do, has anyone else done them, and do they think it was worth it. I know zippy about any of these oil mods.

Intended use is hot rodding, cruising on the street, and a track day/auto cross day several times per year.