Thread: #96 head ?
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Old 07-31-2020, 04:26 AM
Will Will is offline
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Join Date: Dec 1999
Location: Pugetopolis
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Note that the factory hardening was not a separate seat of a different material that was pressed in. Factory hardened seats were either "flame hardened" or "induction hardened." The "flame" hardening was the first technique used, in '72 I believe. It didn't impart as much hardness into the seats so they went to the induction hardening.

Basically the factory used high heat to harden the metal in the heads at the exhaust seat. Once those seats start to wear, it makes sense to put new hardened seat inserts in.

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'72 Formula 400 Lucerne Blue, Blue Deluxe interior - My first car!
'73 Firebird 350/4-speed Black on Black, mix & match.