Ok ... thanks for that info. I've never torn into a Subaru motor before, but I can see it's a flat 4, horizontally opposed motor, somewhat like an old, air-cooled VW. I rebuilt a VW motor a long time ago, but I guess I just assumed the Subaru would be different.
Well ... If I need to split the case, I might as well get the machine work done and do the job properly. :-|