harleyKmodel

Anti-knock additives contain no energy, and subtract from the BTU-per-cc energy content of gasoline.
Regular gas produces more power than anything else, it just needs some mods to accept the conditions that some engines impose on the combustion event.

The higher the octane the cleaner the burn.

Marketing claptrap. Adding what are in essence impurities into the combustion process isn't going to make the burn cleaner.

But I do know that using Exxon Premium will make you taller and better looking. I've seen it on TV.

Av Gas needs oil added for running in race cars on the ground. Very dry fuel as well as designed to mix 14.7 to 1 at 10,000 feet. I used in circle track Trans Ams when running high compression, 200 lb/sq in 420 inch Small Block Chevys. One quart of M Mystery oil per 55 gal drum worked. Also ran alcohol jets 8n the 870 Double Pumper with 2 50cc shooters. #HurricaneHolley 94, 95 96 Alaska Champ. Any less octane and it's back the timing severely or blow the crowns off. Erik K

14.7 is a scientific curiosity, and not necessarily a useful (or achievable) goal or target. Too lean for any power in an air-cooled engine, too rich for good mileage.

For another jaunt into the theoretical—what would the effect be of a tube of pure oxygen fed through a hose into the carb?

I think adding oxygen would just give more heat which is all ready an evil that has to be tamed.

Effect would be holed pistons!!

If enough fuel could be added as well, the effect would be a huge power increase, but without nitrogen to buffer the combustion probably broken parts would result.

I was thinking more along the lines of oxygen bursts of less than a mile or two.

Ok- nitrous works, right? So oxygen mixed with nitrogen—?