Water in oil after rebuild - looking for guidance

I just noticed a heater hose leaking at the heater core connection when pressurized. I tightened the clamp, no more leak and it's now holding 13 psi on the tester. It has held pressure through the entire time it took me to remove spark plugs, turn over the engine, and run a compression check. I found no coolant in any cylinders. All cylinders are running at 150 psi except #7 which is 135 psi. The needle on the cooling system pressure tester does not move when cranking the engine with spark plugs in place.