Thank you...Stuck...to UNSTUCK!!!

Some of the antique Cat guys I know swear by a mix of acetone and ATF.. and maybe some FIRE! Granted, most of them are talking about breaking a diesel loose with the heads off.. but maybe sticking a butane/propane torch thru the sparkplug holes might help.. preferably before you fill the bores with flammable stuff!
These guys wil put a little kerosene in the bores and light it.. heat and cold cycles and moisture locked it up.. might also release it.
Looking forward to hearing about the start up operation.. Good luck!