Tunnel ram, vacuum tuning?

Let me explain a little more clearly. Unisync refers to the device used to compare airflow through one carb to another. Or several others. And t port sync is a reference to the transition slot i believe. Adjusting to the highest rpm via the mixture screws and then lowering the idle rpm by closing the throttle blades will make more of the transition slot available to do it's job. Then the unisync is used to ensure equal airflow between carbs.