Headlamp +12v provision

Most of the wiring in my car is even older... 1963...  Haven't had a wiring issue, except for once with the new stuff I ran for the EFI. Had a wire fall down onto the exhaust and ground out. It was the oxygen sensor wire, and grounding it killed the ignition. Who would have thought that? 

confronted with the same issue in my old classic, and those horrid old headlamp switches with the chronically bad contacts, rather than rewire it i installed two relays, one low one high beam, up in front near the headlamps, and had the headlamp power run the relays instead of headlamps (thereby offloading the horrid switch). then ran a hot wire fromt he alt or something to the headlamp relays, and new wire and lamp sockets from there to Cibie Z-beams (it was a while ago :-)

http://theamcforum.com/forum/eagle-heatlight-upgrade-relays_topic67272_post610194.html

I used heavy and more heat resistant headlamp sockets and made a better, heavier harness for my headlights. I grounded them by the horn relay. I used a breaker to supply power, run through two relays (one for high, one for low). All that goes through the cabin and switch inside is the power to the relays. With the battery that close, and the heavier wiring I found I have to have my lights properly aimed or I get a lot of folks flashing their brights at me even when I'm on low beam. 
The voltage drop I measured was crazy - even when system voltage was over 14 the headlights were getting somewhere between 10 and 11 volts. A lot of the drop was GROUND. The biggest drops were under the hood, not inside, as I had replaced almost all internal wiring when I did the engine swap. I replaced the fuse panel and ran countless new wiring, EXCEPT for the headlights. since that was a different harness, even with the engine swap that didn't get changed UNDER THE HOOD. (I redid the inside wiring as it had gotten wet over the years of windshield leaks across the fuse panel and such)
The link above is a bit more on the project. 

The whole wiring harness for the headlamps is short because it goes only from the relays to the headlamps. I used "jumpers" from the original headlamp wiring to the relays and left the original wiring hidden behind the grill since that controls the relays.
The photos show the two relays in a socket screwed to the inner fender, then the circuit breaker, then the horn relay. The headlights ground behind the horn relay - and the battery cable ground is just inches from that. 
So from the right side low beam headlamp socket I ran a wire to the low beam relay and from the right high beam socket I ran a wire to the high beam relay - the original wiring only powers the relays. Since those draw a pittance, the headlight switch and dimmer switch should last, let's see - I'm 60 - well, they should last longer than ME!
The wiring you see in the bottom photo that runs above the battery against the fender - that's my new headlight harness. Short, simple.