Let me throw in 2 cents worth to this interesting discussion. I have a good friend that raced late models for several years, back when hi compression big blocks were the state of the art. They got a recipe from a guy that had raced regionally for years with pretty good results His recipe is:
25 Gallons premium pump gas
25 gallons 100 octane av gas
5 gallons toluene
2 quarts Marvel Mystery
oil (or ATF)
My friend said this mix burned VERY clean, had great resistance to knock, and produced some serious horsepower. They never had any problems with combustion chamber deposits or fouled plugs. The toluene is very dry, so the lubricant helped the valve stems live.