I can only relate my most recent experiences. It was always my understanding that the seats in the 8 bolt motors were hardened (induction or stellite), but the last 3 heads F heads I've had done had cast iron seats. Too much time has past to really get a good read on what was actually made At the time and I sense probably some of each. All three heads were not virgin so any induction hardening they had was long since left on the machine shop floor.

Your machinist will know right off. Take it to the bank tha Phil has as much experience and then some as any of the rest of us. The cost of adding hardened seats is not significant when you have the head done... Go for it!

mike