Higher octane gas actually has a lower power output if measuring them side by side. High octane helps in pre-ignition with high CR motors and runs cooler, great in a radial motor, not so great in a V. I think RR/Merlin motors on takeoff had water injection and 50 PSI of manifold boost and liked about 130 octane. Did you know CNG has 130 octane? Gets you thinking about a 14.5:1 street motor on the fart that you can drive in the CA carpool lane!