How can I tell if the seats in a head are hardened ones? My old heads were not original by part number, but I don't know how long ago the engine was done or if the seats were replaced. Thanks

 

what is the casting number in between the two middle spark plugs

 

The heads are C8AE-h. My new set I know has the hardened seats which is why I bought them, they also have the stake marks around them to temporarily hold them when installing. But I don't know if the old heads had them changed. I know they were not original with them but the engine had been redone at some point. Thats why I want to know if there is a way to tell.

 

they probably dont unless somebody has installed them. if i'm not mistaken D2's are the first year for hardened seats.

 

If your heads have a seat in them, it will be noticable, like an insert under the valve face. On the old ones, there is no seat and the valve actually contacts the head. The reason for leaded fuel in the old days was to coushion those contact pionts.

--Mike