It appears all the usual suspects have been addressed. There is no doubt in my mind that the out of spec. engine rake is exacerbating the problem (whatever it is). I KNOW, "the engine has always been at this angle and no problems were experienced." However, Rodger is now in cruising mode (meaning loaded for cruising) and I'm wondering if he is slightly "stern heavy" which would increase his engine rake. This would be further increased once he is underway and powering into head seas. IF, as has been mentioned, the major portion of the crankcase oil is now in the rear of the pan, it is possible that the number one rod is dipping into the oil, and at the rpm he indicates could (probably would) cause foaming.

An added consideration is where the oil pickup is located in the pan (I no longer have the books on the 2GM and can't recall exactly where it is located) the 2GM is slightly different than the newer 2GM20/30.) Most oil pick-ups are about mid-point in the pan. If the oil pick-up is in frothing oil it will be intermittently starving as the boat surges ...well, that would be a problem as well. Should the oil be frothing due to the above conditions it can cause no end of problems.

The fact that his engine starts and runs well indicates compression is not a problem - he also mentions only ordinary light grey smoke at start-up. The gold standard for quick and easy compression testing is to go down to the dock in early morning when the temperature is 40-45 degrees or lower and start the engine, if it starts within two or three revolutions the compression is fine. Diesels with poor compression do not start well in cold weather! It is of course difficult to diagnose engine problems long distance and I could be way off base with any or all of the above conjecture. These are just the things that ran through my mind as I read the thread.

In his position I would reposition interior ballast (stuff) to make the bow slightly down when at the dock - I would cut back on the rpms when under way, it sounds like he is outdistancing his companions as is. 2200 rpm instead of his reported 2700 could make all the difference. Engine dipsticks are notoriously inaccurate due to different engine rakes. I suspect he may have too much oil in the crankcase to start with.

There is one other 1000-1 shot. There is a spring loaded ball bearing check valve just behind the oil filter to adjust oil pressure before entering the filter - I have heard of a case where this valve failed (stuck open, broken or weak spring, I don't recall now) In any case some pretty good mechanics spent a lot of time on this until they discovered how high the oil pressure was - that engine was reported to be leaking in several places under high rpm.