One night, while driving through the grove of Eucalyptus trees on US 101 near San Juan Bautista, California, I realized that the sealed beam headlamps on my Alfetta were inadequate. This is the same road that Scottie Ferguson and Madeleine Elster (Jimmy Stewart and Kim Novak) took to Mission San Juan Bautista in the film Vertigo.

A modern car had pulled up next to me in the other lane and I suddenly saw the road ahead. That’s when I realized that I had to improve the lighting on the Alfa Romeo.
Research turned up 5.75 inch (146 mm) Cibie H4 (low beam) and H1 (high beam) headlamps for the quad setup I needed. For the H1 headlamp, I used Osram Silverstar bulbs (NOT Sylvania Silverstar) and for the H4, I used Narva Rangepower High Output Plus 30 bulbs.
This setup is more economical than the Cibie Complex Surface Reflector (CSR) headlamps and I’m only replacing the right side headlamps in my crashed into Alfetta. Osram Sylvania produces a Xenarc HID conversion kit I’ve seen for US$ 588.
I’ve read that installing relays was a good idea for the Alfa, since the factory setup has all the headlight current going through the switch on the steering column. Daniel Stern has covered this and other lighting topics so thoroughly that I didn’t have to look anywhere else.
Comparing the Cibie headlamps to sealed beams is literally like day and night.