By mixing those two together that will give you a 111 octane average. You should only increase the octane in your fuel when the compression calls for it.
Octane of that level should only be ran on an engine that is pushing out 195lbs. of compression or higher. Running a higher octane than the compression calls for will only slow the engine down. Due to the extra burn that is required to finish out the fuel.
155lbs of compression requires only 93 octane to run properly. 160-170lbs requires 101 0ctane.
