carbs flooding

My Z750 floods in to the air box. I got a different set of carbs and they do the same fuel pissy out of the back of the carbs all 4...?? into the air box

this would normally be caused by poorly seating float needles. Remove them and inspect for issues. check that the screen above them doesn’t have rust in them. if they do, check the tank.
also verify that the float level is correct, do a bench measurement, then after they stop leaking , by using the clear tube test.