[WardL]

You said if you mix regular (87 octane) and high test (91 octane?) you will get a higher octane? Maybe if there is lead in the high test, but if you are just mixing retail gasoline, the resulting octane will be pretty close to a proportional blend of octane. A 50/50 blend of 87 and 91 makes 89 octane. That's the blend to make the retail midgrade gasoline. I agree when you add the octane booster you will get a higher octane.

Maybe I missed your point?