WHen the engine is cold - take off the radiator cap and hopefully the
radiator is full up to the top - start the engine - if there is a
compression leak to the coolant - the coolant will really jump outof
the neck of the radiator. Your oil will also be congealed if any
coolant gets into it. You probably have normal water vapor - cats
cause a lot of it.

Generally people who have warped a head on a honda i4 (overheating does
this very handily) don't have a lot of luck when milling or replacing
the head at keeping head gaskets in place..