Replacing damaged heads 2.7

[farleyd]

Hi to all, 2 of my 2.7S heads are cracked around valve bosses. I have two spare heads but they are slightly different. Same part number but the surface that mates with the cylinder head is even/flat, while the 4 original heads have a elevated surface sitting around the studs.

Any clue? Can i use them anyhow?

Thanks!