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Message: <blockquote data-quote="Shawn Hennessy" data-source="post: 538978" data-attributes="member: 53998">It isn't the octane that is at issue with the valve seats.  The concern is around unleaded gas....but not in your application.Unless you're drag racing, pulling a heavy load constantly (i.e., a truck towing a trailer) or something similar that puts a lot of RPM's and a lot of heat (like where the exhaust starts to get red, running lean EPA-style mixtures), there is no big problem running unleaded in an engine without special (i.e. hardened) valve seats. If you were running high compression or a blower...that scenario might push you into the territory where hardened seats are needed. Like Tiger says, the pingin/predetonation is the issue with lower octane.  I remember dudes buying octane boost and adding it to their 87 octane at fill-up.  It seemed to be about the same in cost at that time, as premium gas.</blockquote>