The easiest way to get to the ignition barrel wiring (especially on my car with all the extra under dash wiring) is to go through the fuel gauge hole, you can get to the barrel wiring from directly below it if you know how to remove it (shown later) but you've got to be careful around the headlight switch wiring, disturbing wiring on these old beasts can sometimes send you straight to hell...

The first step to removing the fuel gauge is removing the dash, the dash face plate on the HR is held by two screws at the top and the choke and wiper knob at the bottom. The screw shopwn is at the top right corner.