Sealed Beam Headlights

if i can get RHD H4 conversion lamps to fit US cars to make them legal in the UK
you must be able to get the appropriate Left hand dive pattern in the US i.e there is enough standardisation across models manufacturers and indeed continents to give a wide range of options for an H4 or similar conversion, that differs cosmetically only in the logo on the lense from what was there originally.
I would never go back to sealed beams

relays and H4 and a new headlamp switch (when that thermal cut out wears out it will leave you stranded in the dark) from a reliable supplier all good

lamps hella
bulbs philips
switch Richard Ehrenberg

No problems for 10-15 years

Dave