Gives me the eebeejeebee's.....That's how my aluminum Hemi was. Very inconsistent with oil pressure, then it blew up. Could be any of the things you mentioned, or it could be a whole list you didn't. Best way to look for it is with the engine on the stand and a drill motor thru the distributor hole to prime it. Try all your ideas out one at a time from the simplest to the more complicated. Make a list and start crossing things off you tried. I spent a season trying to find my issue.