I'm enjoying the ride as you sort out the issues 20 years of sitting in weeds can cause. It does sound like the parade truck is well on it's way to being a driver. For some reason I'm also reminded of the "Whole Earth Catalog" from my misspent youth.
added in edit: It occurs to me you're at the edge of the WIIT (While I'm In There) rabbit hole. It does sound like a head gasket is called for. Not a big deal usually. But then with the head off it's fairly easy to drop the pan... pull the rod caps... push the piston/rod assembly out the top of the block (after knocking the ring ridge out of the top of the cylinders)... replace rings, deglaze the cylinder walls with a hone or just sandpaper... reinstall with new rod bearings and do a cheap inframe ring job.
But wait, WIIT why not just go ahead and pull the main caps and work new main bearings in over the crank, replacing in the cap.
But wait, might as well just pull the engine and since it's only a 6 cylinder have it bored, new pistons, hot tank the block, get the head rebuilt, new cam bearings, new water pump and oil pump.....WIIT
Good Luck!
Ron
Last edited by moparguy; 05/25/2017 2:17 PM.