Use pump low grade with 10% ethanol content and jet for it. That engine with a 2bbl will be starving for oxygen and ethanol carries in liquid oxygen. There is no need for anything above 89 octane with that low of compression and low cylinder filling. Take the same engine and put a good induction and exhaust on it that is tuned to fill the cylinders with resonance tuning and really good flow or even over fill them then you "might" have an excuse to run higher octane with the lower compression.