About 2/3 to 3/4 down on this web page there are pictures showing the
oil passage to the valve train.
https://www.diyford.com/ford-fe-engi...omplete-guide/
The
oil does go up through the slop in that head bolt, so you want to be careful not to plug off the
oil to the valves, with a bunch of thread sealer. You will note that there is a water passage on the other side of the head bolt that the oil passage uses. I would have to see what the sleeve looks like to say if the low sleeve is causing the problem or not. There could be a crack in the block that is allowing oil to get into the coolant. Anyway I suspect these four oil passages to the heads are the most likely place for this to happen.