[Fr. Frank]

nuthinfancy said, inter alia

since the first post stated that there is a throttle body the there wouldnt be any needles or seats used on carbs...

A LESSON IN INTERNAL COMBUSTION.
Every carburetor has a throttle body.
It's where the slide or butterfly is located. Open the throttle, the slide goes up or the butterfly swings open. The fact that is interrupts, or "throttles" the intake venturi is what makes it a throttle body.

In throttle body fuel injection , the fuel is sprayed into the airflow downstream of, or after the throttle body without the need for an air venturi to atomize the fuel, as that's a function of the injector. This is even though many TBFI engines have a throttle body venturi anyway, to further atomize fuel, and to enable the engine to run even if the injector does not spray a fine mist because of dirt in the injector.

In a carburetor throttle body, the fuel is pulled into the throttle body by manifold vacuum and/or pumped in mechanically just before or in the venturi, with the venturi performing the function of atomizing the fuel for good combustion.