Hence my thoughts to put a cooler in the cylinder head feed, it only cools some of the oil so is unlikely to over cool it, and it helps cool the head.
My thoughts behind cooling the head are simple, the basic design of the head isn’t that far removed from what was initially designed as a low compression 500. So my 10.5:1CR 850, and even worse when it becomes a 920, is really asking a lot from that original design. It seems to cope well enough, but a little additional cooling there would seem to have zero down side and potential upsides, to my mind at least.