I'm having some issues w/ the Taurus 3.0 Vulcan engine. The engine overheated and now has misfires in cylinders 5 & 6. Am I correct in assuming that at the least, I have a bad head gasket? Coolant may be leaking into the cylinders, but there is no white smoke and the plugs look ok. My plan is to replace the head gaskets and thermostat. Then flush out the cooling system. Water pump was replaced previously. I'll have to double check the heater core for leakage and verify that the fans are coming on before I tear into it.