To be honest, those heads are so old, it isn't worth doing. All 16 seats? If so, your talking a big bill. seat removal, re-cutting seat counter bores, ovening heads, seats, valve job, likely welding in chamber to restore material to work with, etc. Its time to send them to the scrap yard. Likely new valves, surfacing, consider tpossibly guides, erc.The heat treat to be gone by now, etc. They are junk
Frank