Since you have a blown head gasket, you need to assess if any damage has been done to the head in that area as well as the cylinders before you go any further. My opinion on hardened valve seats is that it depends on the condition of your seats. If they are recessed from excessive wear or multiple valve jobs in the past, than I would go with hardened seats, especially on the exhaust. I would not recommend replacing serviceable valves/valve seats for fear of unleaded gas, but if you have to replace the seats from too much recess, might as well go with the hardened ones.
Last edited by 52Carl; 10/02/2013 10:23 PM.
