The fuel jetting is different for ethanol, because it takes more of it than gasoline. We converted a Volkswagen to run on ethanol, and found that dividing the jet size by .49, would give the correct jet size about 104% larger. It also required a hot engine to be drivable, and was impossible to start on really cold mornings. We had to start on a blend and switch it straight ethanol.
Yup, it works for parties, where the nuances of finely aged liquor are not selection criteria. I can remember parties with 5ths of 190 proof in punch bowls in my youth. Sometimes on the sly and sometimes more than one covert contributor. A lot of folks puking, instead of jumping into bed as they originally envisioned.
I've made some damn fine liquors using 190 proof and sampled some fine white lightening, but it was closer to 120 proof, because it takes multiple runs or a compound refluxing still to reach 190 proof azeotropic balance levels, and the moon shiners in our neck of the pucker brush had simple pot stills.
A CA lad that I know, has a compound refluxing still and makes his own 190 proof ethanol for QWET extractions, from cracked corn, sugar, wheat germ, and distillers yeast. It does a nice job, but does impart the unique flavor of corn liquor.