I have a 606 engine, and dumped the whole bottle in when the side resivor was low enough. Can't say i saw any real difference. I understand that certain types of dirt track racers like to use it as they don't use or aren't allowed to use antifreeze, so it's water and Water Wetter to help cool.
I've also heard of people using Water Wetter in water to air or whatever the method is for those types of intercoolers with the same idea in mind, get it cooler, air more dense, more HP. Don't know if that really yields results.