FWIW.
Have a 461 with about 10.2cr/234/244 - 110lsa mft cam.
Before starting complete body work years back(another story...) I mixed 50/50 87 octane(w/10% ethanol) with 93 octane.
After over 500 hard street driving and at least 100 1/4 mile strip runs at 114 mgh, while engine was out inspection on bearings and heads checked perfect.