I think he is looking for the height of the air cleaner with out the air filter. You know how some are dropped base and some are not. Both having a equal height air filter will set at a different finished height about the carb. So if you measure the S&H from where the carb flange is to where the filter will rest and add any 'dome' for the top, and subtract that from the distance from the flange to the hood you have the maximum filter height (leaving some out for movement of course).
Now if that is not what you are looking for, please see Jamos post
Rick