in this image, we are looking at the other end of the main feed, in the oil filter boss area.

Yes, the work has already been done. I did not think about taking pics of this procedure until I had already worked it over with the carbide burrs.

If you look closely into the lower hole, you can see an "eyebrow" at the bottom. That eyebrow is the diameter of the original drilling. That original drilling was not centered on the cast-in passage; noe was it the same size. It is now; and it has been opened up more at the top and side to let the oil flow.

The problem at the bottom of the upper hole was one of a couple of steps left by the drilling of the passage for the threaded bolt hole and the differences at the bottom surface for the main gallery feed passages. I ground away the steps at the bottom, and radiused what I could to let the oil flow.