The 848 head on a 235 from the factory was 8.25:1 compression. I would suspect that if you had a .060 over bored 261 with flat tops you would crank at least 160psi = 9.0:1 minimum. Still pump regular gas.
"Drugs are money, money is power, power is security." - Kent Heiner
Nedrow population 2212
Carbon footprint family of 2/11 tonnes of CO2/yr
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