My 53 had the same problem, the PO left the hood off for 2 years. I put a hay bale on the back, popped the clutch, nothing. Tryed diesel, help a little. Tryed penetrating oil, helped more. Removed head and whole frend end. Welded big nut onto flywheel. Played with it for a little while everyday for a week. Got it unstuck and she runs like a champ!!! also, did not have to rebore or new pistons, rings and all that stuff, just had to redo the valves. good luck
