How do you know it was water vapor coming from cyl/plug hole ??
If it is truly a low hour rig you have two choices, ride as is or go all out, to an extent. As mentioned, sending off for porting this time of year, depending where you live, might not be back in time for spring riding. You would have to call to see what lead time is right now, then decide.
Even porting or head mod/ cool head/domes should get welded crank. As mentioned, there is no easier case to split than a banshee.