It's much harder to put the motor on its nose in the drill press, so I drilled all 4 plugs by hand. Actually for the small plugs I went right to the 1/16 NPT tap without drilling. But I could not get the 3/8" NPT tap started. As I was getting frustrated I put it aside until after Oshkosh and ordered some 10MM bolts so I could get the case nose down on the drill press. What I did on the other side was to use the chuck to press/center the tap into the hole as I turned it. That worked great.
Here I've bolted an angle across a couple of 10MM holes that serve some purpose on the car. I clamped a second angle to the first one. I also found some nifty large flat head torx 6mm screws from my Saturn junk box and screwed them in by the crank exit/snout.
Here it is in the press.
I clamped those angles to the table and shimmed below the screws & snout. I made the screws level with the snout.
Lunchtime over - will tap it tonight.
I'd rather be lucky than good.