At one point in my career I hauled gass in the US. When the trucks fill up at the At one point in my career I hauled gas in the US. When the trucks fill up at the refinery they only have 2 grades, Regular and unleaded. At the gas station they only have 2 tanks under the ground. How you get the different mixtures of octane is that the pump “mixes†the two gasses together. If I had more Regular gas than would fit in the tank I would just add it to the unleaded side or the other way around. I was not the only one that would do this. Who wants to drive a truck 300 miles the other way with only 20 to 150 gallons just to unload and drive back home. So unless you want to stand there and test the octane levels every time you fill you only get close. I have installed a K&N inline fuel filter between my tank and carbs. I don’t notice any performance difference but it makes me feel better. ;-)
