the complete guide to sealed headlights conversion

Sealed headlight beam – the complete guide to sealed headlights conversion

Classic cars and trucks use sealed-beam headlights which have the bulb, reflector and lens as one unit. While there are different types of headlight housing, if there are screws holding a trim piece around the headlight and another metal ring holding the headlight itself then the headlight is a sealed beam. People born after 1990 or so have grown up in an automotive world where “every car” has a composite headlamp assembly, uniquely designed to be make- and model-specific. If one light within the assembly burns out, you replace just the bulb. If you have a bad headlight fuse, you can either fix it or buy a replacement. If the unit cracks, you must buy a replacement that fits your car and your car only. This was never the case! For approximately 45 years, cars were required by law to use “sealed beam headlamps”. What are they? Sealed headlight is a headlamp assembly consisting of an enclosure with a bulb in front of a lens made completely of glass. The entire unit is sealed (the reason for the name) and no part can be replaced separately. If the headlight stops functioning or breaks, you change the entire sealed beam light and they were, and still are, very affordable.

Need for sealed headlight conversion 

need for sealed headlight conversion

If you have a classic car with sealed beam headlight units, the odds are that you will like to upgrade the styling of the car and in general want to keep the overall appearance stock. Classic cars have sealed-beam units, which are relatively easy to deal with. Classic cars have sealed-beam units, which are relatively easy to deal with. Certainly, you have seen the cars and trucks with their custom Halogen to LED headlight conversion assemblies –boring factory units replaced with all-chrome or all-black headlight units, full of bright halos and LED strips, lighting up the night. If you are running what we call “sealed-beam” headlamps, it is proper to know that there are a lot of sealed-beam conversion options. These allow you to replace those one-piece units with lights that are equal to and better than some of the custom composite headlamps.  Cars and trucks started using rectangular sealed beam lamps as an option in the mid-70s. If you had 2 (combo low/high), technically that is 200mm; 4 of them (2 low beam and 2 high beam) are 165mm each. Most lighting manufacturers name the small ones 4″x6″ and the larger ones 7″x6″. If you have doubt, check the number of electrical prongs in the back. Combo low/high beam lamps have THREE prongs and separate low beam or high beam sealed beam lights have TWO prongs.

Guide to sealed headlight conversion

Guide to sealed headlight conversion

You now know what is currently installed; the question is what you can do to liven things up? Let us start with the simplest choices first; 

  • Round and rectangular headlamps are available and they include separate, replaceable bulbs. Combined with improved lenses and reflectors, they dazzle you with their significantly improved light output. Unlike the dim sealed beams that require complete replacement when they burn out, these separate lens/bulb units require you to only reach in and replace the bulb as the lens stays in place.  
  • If you want more, get lights with all-chrome or blacked-out casings and use them as a styling statement, even when parked. Light assemblies in the same size and shape as your factory ones are available in halos or LED strips; just the same way you see them on the newest BMWs and Audis. Of course you can get fully functioning low and high beam lights. 
  • How about halos in red, amber, green or blue? You can set it up such that the amber halo also functions as a turn signal. (Don’t forget that in many parts of the U.S, blue, red, or green front lights are considered for show use only. It is a good practice with any of these lights to check your local laws for the appropriateness of on-road use.) 
  • Perhaps the ultimate is an LED conversion kit. These multi-faceted lamp assemblies have a unique look with their low/high beam LED lights and its bright LED halo rings. 
sealed beam headlight conversion

Whichever you may choose, we may have saved the best news for you as these lights are really easy to install. Sealed beam headlight by definition requires little technical ability to change. They were designed to be removed and changed with just a few screws and the conversion kits are installed in exactly the same way. Compared to the composite headlamps on newer cars, some of which may require front fascia removal, you’ll be done in no time. Everything from a ’55 Chevy to an ’85 Mustang can showcase the vast improvement in its front headlamps once a sealed headlight conversion kit is installed. 


My recommendation to other classic car owners is to upgrade your headlight bulbs and restore your headlight lenses with headlight restoration wipes, but be knowledgeable with your purchases. Know that if it comes with no branding or warranty, it is perhaps garbage. If it feels capable of swerving an artillery shell and lights your way like the North Star, it may be worth your hard-earned money.

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