I hadn't considered a less-than-flat mating surface. I heard the same things about headers being problematic on these, so I have a used manifold on it's way from eBay. I'm hoping to have it by the weekend. I'll check it for flatness before installing.
Since the engine is on hold, I turned my attention to the headlights. I'm well aware of the reputation Lucas electrics have, but I'm also equally aware that this wiring's been "fixed on" before. Am I'm talking of the wire nut and electrical tape variety. So I started by just verifying that things were hooked up to the right things.
Surprisingly, they were. So I put on my sleuthing hat and dug in. Testing at the switch, I had power. So I went to the other end of the system, fully expecting to have no power. Except I did. Hmm.
Plugging the lights back in, I still had no headlights. So I tested for power again, with the lights attached and dangling. This time, no power. Hmm.
Checking back at the switch, I still had power. That left the foot-operated dimmer switch or the wiring itself. Testing at the input from the switch, there was power. However, the active leg of the output had none. Ah ha!
To verify the dimmer switch was bad, I used a spare wire to jump the power at the dimmer switch connector and just like that, I had headlights. I ordered a generic dimmer switch on Amazon that should be here tomorrow. Uh, well, later today, I guess...
I was curious why the switch wasn't working, so I tore it apart. It was dusty and has dried grease all over the copper components. So I gave it a quick once over with a brass wire brush. I noted that a plastic post that the mechanism was supposed to rock back and forth on had broken, so I didn't have high hopes. But, I reassembled the switch and gave it a go. To my utter surprise, it worked! I'm still going to install the generic switch, but it was pretty cool to get it working.