3310s are a generic carb. Every one I have ever worked on was pig rich on the main circuit. As bad as a double pumper. Usually took 6 steps or more to get them in the ball park for clean cruising. Then the power valve needs to open sooner and the PVCRs need opened up to bring the wide open throttle ratio back to where it needs to be.

You need an O2 sensor if you are going to start tuning the carb.

This will probably cause an argument, but a cheap (even a used one) O2 will get you close enough on the cruise circuit. Tune the gauge into the green and you will be good as long as you richen up the power circuit. Done it many times. Most guys wouldn't be able to get it any closer with a wide band if they aren't an experienced tuner already.

Then there's the timing ....................