Popular automotive sealed beam sizes are as follows:
- PAR30, PAR36, PAR38, PAR46, PAR56, PAR64
Let me give you some examples.
Almost all the USA vehicles through the mid-1970s used round sealed-beam headlights, either two 7” lamps, or four 5 ¾“ lamps. The 7” lamp is dual beam (one light operates as low and high beam), whereas 5 ¾“ is single beam (running only low or high beam).
5 ¾“ lamp
The fact is, since 1978 all the sealed beam bulbs would come as Halogens (at least, on the USA market), however they have different design from the contemporary Halogen equivalents and that, in turn, required different housing construction. Therefore, even though you get lucky to install any modern size bulb into your car sealed beam housing, you’ll be bound to enjoy poor visibility, let alone to blind the oncoming drivers and pedestrians.
We suggest you’d go with ordinary conversion LED or HID kits which provide much greater output while retaining competitive pricing.
As you’ve made up your mind to switch to HID or LED technology while your vehicle uses old sealed beams, you’d need to replace the entire sealed beam light. Besides replacing or modification of the housing is required as well.