I believe that is an adjustable fuel pressure regulator. The reason the gauge is after it is so you can see the REGULATED fuel pressure, not the raw fuel pressure that is put out by the pump (mechanical or electric). Carbs are designed to operate on low fuel pressure. Some fuel pumps produce much more pressure than a carb can handle, therefore the regulator. The gauge is so you can dial it down to where the carb likes it. You really don't need to see fuel pressure from the drivers seat since if your pump is adequate it should remain the same. Also, if you mount it remotely, now you have extra fuel lines running across the engine and that is asking for trouble if you have a leak.
And Cuda Jas, really nice work on the engine!