It sucks, there are 2 screws that hold it together from the top, then 6 more that screw in from under the base plate. If you're doing a lot of tuning you can leave the bottom screws out to take the top off easier but when you're done you'll have to put the screws back in at some point. But yeah if you need to change jets the carb has to come off to take it apart. Other than that it's a fabulous design IMO it's like Holley engineers redesigned the Thermo-Quad (pretty simple on the inside).
Speaking of which I found my accelerator pump isn't working now for some reason, gotta pull it and fix that now arrgghhh!