were almost certainly made to take the pre-halogen Type A (asymetrical pattern) bulbs, which have an entirely different base than H-4 bulbs. I have seen in a catalog from England once upon a time about 25 years ago, halogen bulbs with an H-4 bulb and a Type A base, made to brighten up the old style Euro lamps without replacing the whole headlight unit, and I have one here in my headlight collection (not for sale), but they certainly might be hard to get nowadays. On the other hand, if you're really good with a soldering torch, you can carefully remove the H-4 base and then carefully align and fit a type A base yourself -- I did it a few times for an old Volvo 1800S which had been fitted with the Ferrari-style Marchall lights popular in the aftermarket in the early '60s. The wattage is only slightly higher for the H-4, but the heat generated is much greater, so it may cause old style reflectors to deteriorate.