Looking at the inside (engine side) of the cover. The piece that serves
as the port  for oil returning to the filter cavity is visible in this photo.
It's the shinier cylindrical shaped part that's positioned at about one
o'clock on the cavity wall ,just to the left of the channel that feeds oil
into the crankcase. It goes through the outside of the cover and
penetrates the filter cavity and is welded to the cover on the outside
end and the cavity wall on the other.

Looking into the cover with the filter removed. You
can see the oil hole that feeds (oil leaving cavity) the
engine, and the filter bolt hole. To the right of these, in
the wall of the cavity, you'll see 2 holes,one at about
2 o'clock and one at about 4 o'clock. The hole at 2
o'clock is the end of the welded in piece. The one at
4 o'clock is the original hole. It should be noted that
this hole has to be plugged for this modification to
work as that is the only way to divert the oil out and
into the cooler.If the hole isn't plugged the oil will
simply take the path of least resistance which is the
original passages.

The front of the cover showing the ports and filter cavity opening
from a 3/4 perspective.

Looking at the front of the cover.You will recognize the
tach drive hole near the gasket surface of the cover. To
the left of it you'll see the 2 welded in ports which are
drilled and tapped for 1/4"NPT. The lower port is the
outlet and is welded on over a hole drilled into the
passage between the pump and filter cavity. The top
port is the return into the cavity from the cooler and is
integral with the piece that penetrates the cavity.