drill all the way in with a 1/2" bit. drill/tap the unthreaded & small threaded hole(s) to 3/8 NPT. plug the center threaded hole with a 3/4" fine thread bolt (a harmonic dampener bolt works great). smooth your work in the passages with a tootsie roll. deburr the right angle turns where the (2) horizontle passages meet the vertical passage, the lower one is easy to access & the one deeper in, have a helper shine a light in the horizontle passage as you reach it in the vertical passage with a porting burr with a longer shank. In order: drill with 1/2 then deburr corners then tootsie roll everything then drill/tap holes to 3/8 NPT & maybe a slight tootsie roll useage right there where you drill/tap for the 3/8 fittings to elim any sharp edges. EDIT drill the #5 main cap to 1/2 along with the pump passages. check cap to block & pump to cap oil hole alignment (want 1/2 ID unobstructed from 3/8 NPT ports to main gallery). deburr/smooth everything. MORE EDIT actually 1/2 ID from pickup screen to vertical gallery including every twist & turn.