/6 endowed with major GUNK

Just curious but where is the sludge gonna hide on a drool tube slant with the valve cover and oil pan off? The oil drain passages in the head are massive, you can reach the cam from the top and bottom without pulling the head. In most cases I would agree that hot tanking is in order, but I would be tempted (depending on sludge hardness) to scrape, flush, and run it.