Bob is correct about the 10# difference (with oil).
There's a ring issue in #4 because the oil brings it up 15#.
Compression tests should be done with the engine @ operating temp. They would be around 100 on the ones that reach 85 cold.
If; there's no oil in the water or water in the oil, you have an "overhaulable" engine there.
Or; you could rebuild it.
Or; you could just change the rings in #4 and a 'valve job'.
Good luck.
