John Deere R Pup Engine

[Dan The D Man]

so ive got the deisel engine unstuck which was very easy but ive seem to have found the source of why they parked the tractor and left it for 30 years. its hard to explain but ill try, when u take the head off of the pup cylinder on the pulley side. there is 4 water jackets around the cylinder and valves. well the bottom water jacket has a hole in the cast so the water goes in the top and out that golf ball size hole. my question is how can it be fixed???? or do i have to get another block for it????