New pump (1730141) in, and engine put back together. Cranked the starter to evacuate the fuel lines and had oil pressure before the first start. Oil is new, I will change it a few more times in the next 10 engine hours.
I am working on a circuit to shut the engine down if the oil pressure gets too low (I am somewhat of an electronics nerd.) This problem and the related posts have me worried it may happen again when the machine is alone and idling. The body of the new pump measured about .060 over the old one, hope this fixes the problem.
The photo shows the new pump and the new relief valve.
I have put 150 hours on this machine since the first of the year, I am so thankful that this did not happen in February!
All in with the sending unit, shop manual, relief valve, and pump, just under a grand, I think myself lucky it wasn't $7,300 for a reman, provided the block and crank were still salvageable.