So today I experienced white smoke bellowing out of the exhaust. Tap the gas, it dissapears idling it just sends it. My immediate response was blown head gasket. I have checked the dip stick, no milky oil or high level. Opened valve covers, i have black oil. Except for some light miklyness on the top, insode of cover. I belive this is just moisture. When i opened the hood. My overflow coolant tank was full and was spewing some outside. I relive psi on the radiator cap and the overflow tank bubbles. Radiator has some coolant left in it but not much. No coolant leaking external of the radiator, pump or outside the engine.. did a psi test on the radiator cap, good. The system didn't hold. Got it to 11psi and I can see it very slowly dropping psi. Spark plugs are next to inspect before I will start to take parts off. Oil smells and looks like oil, coolant smells and looks like coolant. Its a 350 sitting in a 86 c10. Any other advise or tips are greatly appreciated before I go tearing this motoar apart. Thanks in advance.