Recommendations for cylinder head rebuild or service?

[70Ambo21V7]

74 Eldorado heads, appear to be low mileage but have had work done on them. Would like to have them cleaned up and  looked over to confirm they're good to go or fix them if not. May need to be updated for unleaded fuel if they haven't been. They came with a low mileage engine I'm using to give new life to my Ambassador (already an 850).
Are there recommendations on this type of work?

[Antietam Classic Cycle]

IMO, there's nothing that needs to be changed for unleaded fuel. The seats are already harder than those of a Mack truck engine's (so says my machine shop). I can rebuild them for you. https://www.facebook.com/AntietamClassicCycle