How to repair valve guide boss

Was taking cyl head #2 apart, and discovered this crack. This is 2nd crack now, 1st one was on other head and in bowl area.
This one looks worse. These heads were freshly machined 25 years ago and have been bagged and stored.
This crack hasn't migrated any deeper than where the seal starts.
I'm thinking maybe an epoxy of some sort?
Suggestions?
Thanks