Obviously you have never ran an O2 sensor to see how rich those 3310s are at cruise which A)wastes gas B)washes down the cylinder walls C)leaves extra combustion chamber deposits D)dilutes and blackens the oil E)stinks up the place.

Our engines are much more tolerant of overly rich conditions than they are of lean ones. And overly lean conditions can damage our engines much faster and more dramatically than rich ones. That is why carbs that are overly rich are so often touted as a "Great all around street carb". Their very real down sides are not nearly as obvious.

The 3310 can be made into a pretty good street carb fairly easily and is worthy of consideration. But making it in into a truly "Great all around street carb" is another matter entirely.

Just because the carb doesn't exhibit any nasty driving habits by being too rich does not mean that it is not slowly doing real damage to the engine. A carb does not have to be perfect to be acceptable, but there are more things to consider other than it drives okay. A cheap narrow band will help out lot with these 'universal' carbs. Well under $100 will set one up. For a street car, the cruise is the place where the car spends a lot of time typically and is the area that should be addressed. A properly sized carb will be cruising on the main circuit which is nearly always easily adjustable. A narrow band can get you into an acceptable cruise ratio without too much hassle.