GlowShift recommends the adapter nut be tightened to a little more than
hand tight. That didn't feel tight enough to me, so I tightened it a
little more than that. But don't tighten it too much or it will distort
the rubber washer that comes with it and leak. The adapter has four ports.
Because I was only adding a pressure gauge, I plugged three (the adapter
comes with plugs) and screwed the pressure sender (the sender comes with
the gauge) into the fourth. Use Teflon tape around the threads of the
plugs and sender to prevent leaks.
I oriented the adapter so the sending unit was protected by the plastic
stone guard. That makes it a little difficult to connect the wires and
see the terminal markings, so connect the wires up before installing the
adapter. Be sure to mark which wire is the ground and which is the sender
wire. I took the ground wire up to a ground terminal in front of the
battery; the sender wire goes into the cabin as shown in the next picture.