Inner sactum oil galley plug

dibbons said
OK, I am pretty much convinced I should remove the little non-threaded welch plug under the number 5 main bearing cap (need to think of a way to extract it) and the hex end threaded plug inside near the distributor/oil pump drive (which for now is basically stuck and won't turn-need to figure a way to extract it, too.)

To remove the plug insert a rod down through the passage where the oil pressure (or gauge line mounts) sending unit mounts and just tap it out.
I used a long push rod down through there to tap it out.