Coolant mixing with oil

Hello, it was ran overheated for fifteen minutes or so and I cracked the head.
I have since replaced the head with a brand new one. However, I still have coolant mixing with oil. When running it will start to leak within fifteen seconds and when shut off, oil pan is mixed completely. I have drained radiator when replaced head gasket, no oil in my coolant! Twice. I thought I did a bad gasket job twice. Do not believe that anymore. Took block to a shop and verified no cracks in block. Timing cover is good. Best guess they had was overheated and I changed water pump at that point. They believe I did not properly seat water pump gasket. I admit that is a possibility. They also offered the possibility I warped my intake manifold and is mixing there. However I have put this motor together twice and want as much advice as possible before going for number three.

Also, they said I need to have cylinder walls bored.020 and block deck re-faced due to small defect between cylinder number four and water tube. Defect is right in fire ring area.