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Old 12-08-2012, 12:00 AM
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Default Re: Running a high compression engine on pump gas

The 496 in my Chevelle has 11.2-1 compression with square port closed chamber heads, and runs perfectly on 92 octane. The key(s) to making it work are 1) cam timing (needs to bleed off some cylinder pressure @ lower rpm), keeping the engine coolant temps ~160°-170°, and a nice, conservative timing curve--in this instance, 14° initial and 36° total, but it doesn't come in fully until ~4000 rpm. (no vacuum advance either)

FWIW, YMMV.
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