Here is the Milodon gear drive #13600 that is listed for small block Mopar and Chrysler 331 354 and 392 hemi. I am thinking that someone in R&D was concentrating on the mounting holes, and not the location of the early hemi oil galleys.
My question is would you use a cup type plug in each hole, or would you tap them for threaded plugs?

1/3 of each hole is left open.

I would probally tap them, but look inside those holes to make sure there are no cross block oil passages in them first, go from there

I tap those holes for plugs

Thanks. And yes, there is an oil passage about 3/8" in on each side.