I went with Cibie E Codes on my '70 Cuda
They've skidded pretty badly from what they used to be, and there are much better options now, but they're still fairly respectable.
and used the Hella Universal H4 harness with relays.
If it was sold to you as a "Hella H4 harness", then...tilt! Hella doesn't make headlight harnesses, but there's no shortage of fraudulent sellers claiming to sell such an item. You'll want to put a skeptical eye on that harness; most counterfeit ones are built with unreliable poor-quality components.
For bulbs I used PIAA H4 15224 Extreme White Plus Bulbs.
Oops…that was an error. Easy one to fix, though. Any of the bulbs claiming to produce "extra white" light (or super white, hyper white, platinum white, metal white, xenon white, etc) as its main promotional "benefit" is best avoided. It doesn't matter whose name is on the bulb -- Sylvania SilverStar/Ultra or ZxE, Philips BlueVision or CrystalVision, Wagner TruView, anything from PIAA or Hoen,, Nokya, Polarg, etc. -- all the same scam. They have a blue-tinted glass, which changes the light color a little, but blocks light that would reach the road if the glass weren't tinted, so they give you _less_ light than ordinary bulbs (not more). To get legal-minimum levels of light through the blue glass, the filament has to be driven very hard so these bulbs have a very short lifespan, and there's nothing about the tinted light that improves your ability to see -- the opposite is true (less light = less seeing, no matter about the tint). Sylvania got spanked to the tune of thirty million(!) dollars for false and misleading "upgrade" claims for Silver Star bulbs (see
here) -- and those are among the least-bad of an overall bad product category, so the math kind of does itself, but if you want to check the figures yourself, here y'go:
Sylvania ZxE H4, as sold (with blue coating on the glass, very similar to the blue bulbs Sylvania makes for PIAA), operating at 13.2 volts:
1410/860 lumens, high/low beam
Same bulb with blue coating removed, operating at 13.2 volts:
2000/1320 lumens, high/low beam
PIAA's line of bulbs is pure bulk wrap, and they're all massively overpriced. Lose/lose deal.
Bulb selection matters a
lot to how well you can (or can't) see at night; see bulb test results posted up
here (poster is known to me; he's a straight shooter). The current best pick in spec-wattage (60/55w) H4 bulbs is the Tungsram (GE Europe) Megalight +120; ping me if you want some. Other excellent picks include Philips X-treme Vision (really low price on 'em as I type this,
here—makes them the top pick for cost-effectiveness; I can't touch that price for the Tungsrams and the difference between the two is small).
And lamp aim is by far the main thing that determines how well you can (or can't) see at night with any given set of lamps, so this is crucial: you will need to see to it that the lamps are aimed carefully and correctly per the "VOL" instructions
here.