my holley nhas never leaked, and if it did it was something that was my fault not the carb's yes depending ont he intake u will spill a little fuel no big deal just dont like a match like my friend did other than that a holley will damn near out perform any carb out there if you dig into them and take a chance to learn once you understand them, you can make them do anything within reason of you could buy a demon and never have to touch it !