340 coolant in oil

That is certainly logical.

Can you tell us any more about the poor running prior to pulling this head? Was the motor running hot as indicated on the temp gauge?
The motor was running normal temp. It seemed to run ok until it warmed up, then it began to misfire badly and had no power. It also sounded different as if it was only running on 4 cylinders. It also would die at idle. There was not any smoke coming from exhaust.