If you have the tools & knowledge:
1. Pull the head inspect the air plenums (intake/exhaust), valve seats, and with a clean straightedge check the top of the cylinder block for warpage, followed by measuring cylinder walls (for wear ridge).
2. If EVERYTING looks great, then and only then take your head into to a reputable shop to have it inspected possibly magna fluxed for cracks. If everything checks out then you can consider a valve job and a gasket set.
If it were I knowing what I know about R&Ring the engine in this car and with my access to equipment and tools I would shop the local (for you & me that would be the great Northwest) salvage yards for a low miles same-same engine and swap it out in about 18 to 32 (actual hands on time) shop hours. Including prepping the replacement engine re-installation with all new rubber, O-rings, water pump, thermostat and associated parts.
I know I have traded information with fellows on this forum who can slice that time by two thirds and do it between 6 to 9 hours, but hey I am just that eager any more
Let us know what you do