23 Note the two black wires from the top of the solenoid; either can be ground or power. We took one from each solenoid, stripped them, joined them in a ring connector, and used that as a ground mounted to one of the intake bosses. The other two were combined and plugged into the relay as power. Also note the fuel-pressure gauge and its inline fitting. That’s where we mounted the low-pressure sending unit, affixing it to a brass tee between the fitting and gauge. We then drilled and tapped another 1/8-inch NPT hole in the fitting and mounted the kill switch inboard towards the intake, beneath the hard fuel line.