Did you squirt some
oil into the cylinder and recheck the compression. This would be a sign of a bad ring. Assuming the valves are ok.
For a pressure test you would hook up a gauge to your coolant inlet and start the engine. Rev it up and see if you get pressure. This would indicate a blown gasket or crack. Do you have coolant in the
oil?
Oil in the coolant?
You can also do what is known as a cylinder leak down test but I don't know much about that.
Roscoe