Home made E50 for racing?

You can run that on pump gas. But, there is no reason you can’t do why you are suggesting. It would take someone who has done alcohol carb’d stuff to say for sure if just a jet and squirter change would get you there. I’m not sure how much alcohol (I’ve never used ethanol, only methanol and never with a carb so I don’t know if there is a difference in specific gravity between ethanol and methanol or any other differences) you can get through the internal passages in the metering block and main body before you run into the issue of the passage being the limit not the jet.