Man! This sounds like a crack in the block.. Since the coolant seems to be getting directly into the crankcase and not going into the combustion chamber.
Most head gasket leaks cause the higher pressure from the combustion chamber to enter the coolant passages. You do not give any indication of pressure buildup in the coolant..
Such as blowing steam out the overflow.
Houston we have a problem.
Sounds like you and dad know enough to have installed the gasket properly.. I'd be taking it off again and looking for cracks..
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />