Building a still at home presents problems not the least of which may be legality. Ethanol (still product) readily absorbs water so it would need to be dehydrated before using in a gasoline engine else you may get too much water in your gas tank (not good). Also getting octanes out of your homemade still is nigh on impossible. Octanes are a family of hydrocarbons that are typical components of gasoline manufacture which is a complex operation. They are colorless liquids that boil around 125 °C (260 °F). Homemade stills rarely exceed 195° F in ethanol manufacture.
Ethanol is not the only possible product of distillation. If you have the right equipment and know what you’re doing, you could distill octane out of gasoline, but it would not be very practical to do at home.
I suspect that Olog-hai knows this and is being facetious, especially given that our new friend littlebird seems to be somewhat of a little bird brain.