IS THIS NORMAL?????????

there is a vac line that will go to the box. when your manifold starts to pressurize so will the vac lines and it will go into the box.

and i am guessing if you turn the knob all the way to nothing then it wont retard anymore than the factory computer will. i havent used one myself so i'm no expert.

The box would probably use an optional MAP sensor. That's how my box works atleast (though I just have a TRC and no MAP for the box).

If you just use a box and TRC type device, the box and TRC are what modify the retard.