Sorry Jeff - did this mod maybe six or seven years ago but a Google this morning for Hella 5.75" round H4 conversion shows
Hella H5006 Sealed Beam Conversion 5.75" Round 002850001 for the outside hi/lo lights, and HL71157 5-3/4" Round H1 High Beam Headlamp for the inside.

Again, I used high temp RTV silicone on the rubber boot that seals the bulb at the back of the lens as I was concerned about dust or water leaking in and fogging up the bulb, specially when the buckets of my C2 were closed. This has not been a problem.

You can look around for the H1 (high) and H4 (high/low) bulb of your own preference. You can spend more (PIAA) or less but I've been happy with the GE NightHawk H4. Resist the idea of choosing the rice mod blue or yellowish options and just go with a crisp white, good quality mode.

In a moment of "more is better" weakness I considered actually running all four as H4, using four low beams at once but this is illegal and I travel too much to do anything that might draw more attention from John Law. The two outside H4 hi/lo are sufficient, and no additional front lighting is required. However, I'm still looking for a good red fog light for the rear, with perhaps a pulsing switch, as my '65 still does not have an emergency flasher option.

I find myself doing a fair bit of night driving in rural areas and having a wider, more clear view gives that added insurance and ability to avoid the inevitable road obstacles or critters. Nothing worse than hitting something out in the middle of nowhere, far from home, just because you "didn't see it/in time."

DEFINITELY do the direct wire relays mod though!

 

What's the reason for adding "relays" ?

 

So the higher current draw for the lamps doesn't go through the headlight switch; it only switches low current to operate the relays.

 

As posted above, read this article.BRIGHTER HEAD LIGHTS Great website, a must read.

 

If you measure the voltage at the headlights, when the lights are on, you will see a lower than optimum voltage (depending on Vette vintage). Probably in the 10-11 volt range due to the resistance of the wiring gauge and length, and the switch contacts, etc. Using relays will shorten the path considerably and raise the voltage back up towards 14 volts, increasing light output considerably.

Below is the circuit that I used for the 62. It has a couple of added fuses (3 & 5 amp) due to a "defeated" circuit breaker in the headlight switch, but is essentially what I would recommend (including coming directly off the alternator or generator circuit). The 20 amp fuse from the alternator is recommended. Note wire gauges used.



Plasticman

 

Can you elaborate more on "defeating" the circuit breaker in the headlight switch, and adding new fuses to compensate? Why did you do that? How did you do that?

 

The headlight switch has an internal circuit breaker. In my case, it failed (no lights - at night), so I opened up the switch to find out what was wrong. The circuit breaker had failed (burnt up the contacts), so I "bridged" it, and then added the external fuses.

Also, if the relays are not used, and someone wants (or needs) to short the internal circuit breaker, then the 5 amp fuse feeding the headlights should be changed to a 20 amp.

Plasticman

 

I would use 12 gauge wire (rather than 14 gauge) between the alt/horn relay, new headlight relays, and headlights.

 

It would not hurt, but it is overkill in my case. The run is really short (if you mount the relays where I did - bracket next to the radiator), and I used the existing wiring the rest of the way (both from the dimmer switch and to the headlights). After measuring the voltage at the headlights (before and after adding the relays), I saw a significant change in voltage and light output.

Now note that my alternator is also on the driver's side (just aft of the relays), so that can make a difference, and like I said, 12 ga. would not hurt if the runs are much longer. Just use wire with insulation rated for automotive applications (heat rating). Cross-linked automotive wire can withstand much higher temperatures than PVC wire.

Plasticman

 

It looks to me that the low beams would use two filaments; one when used as low beams, and another when the high beams are on.

With the addition of a diode between the tan and green wires, the wiring could easily be modified so that the high beams bring on both low beam filaments further increasing the light output.

 

Will try it this afternoon and get back to you. Sounds like a good idea.

I did essentially the same on my 03 Vette (run the low and high beams at the same time when on High beam, and it does make a difference).

Plasticman

 

Toddalin,

OK, I added the diode (which turns on all 6 filaments when on "High Beam"), and then drove around for a half hour this evening while using only the high beams (for 99% of the time). Can say when on high beams, it definitely made a difference with all the filaments burning brightly. Note that these are aftermarket T-3 bulbs from Lectric Limited. And the alternator is a Delco 10SI (internal regulated 63 amp). At an 850 rpm idle, the amp gauge was showing zero discharge (meaning it was just keeping up with the lights' discharge current), but when I increased rpm, the lights did brighten a small amount. Note also that my tail lights are LED units, as well as are my front running lights, so they draw far less current than stock incandescent bulbs.

I checked the 14 gauge feed wire (at the fuse and at the relays), and the alternator output wire for temperature when I came back (with the high beams still on), and I was able to keep my finger on at each point that I checked.

In addition to adding the diode, I also changed the fuse to a 30 amp (a 25 amp fuse probably would be OK, but I used what I had). Based on some current readings both before and after I installed the diode, the Low Beams draw 9.15 amps @ 14 volts.
High Beams draw 12.29 amps @ 14 volts.
So, with the diode turning on all 6 filaments, total steady state current is 21.44 amps @ 14 volts. This does not take in initial inrush current when the bulbs are just turned on, which will be considerably higher.

See revised schematic below:


Thanks for the great idea. It should help when looking out for those deer that are all over (I have had one very close call with a pack of them that decided to cross in between wmf62 and me).

Plasticman

 

Thanks for the kind words.

Depending on the agency, the ampacity for 14 gauge wire is 25 amps at 140*F (30 amps for 12 gauge). With all six filaments blazing, a 12 gauge, or separate 14 gauge wires to each relay may help a bit as things can get considerably hotter than that under the hood and the capacity goes down with ambient heat.