*Standard 7" sealed beam. Non-acceptable performance.
*Quartz halogen 7" sealed beam. Marginal performance.
*"Sealed" H4 7" lamp. This has a replaceable element (dual filament H4 bulb in any of several wattages) that inserts into a glass bubble on the back of a sealed lens/reflector unit. Rare. Acceptable performance.
*H4 7" lamp. Same as above, but there is no bubble - the hole in the back of the lamp unit is open to the inside of the lens/reflector unit. "Off road only". Good performance.
*H4 8" European headlamps. No chrome trim rings, no aiming bumps on the face of the lens, no DOT approval on the face of the lens. Replaceable H4 bulb. Good performance.
*H5 8" DOT-approved headlamps. No chrome trim rings, but has three alignment bumps cast into the face of the lens, has DOT approval on face of the lens. Stock on '88 - up USA 928s. Good performance.
"H4" and "H5" are bulb types - dual filament quartz halogen bulbs that fit into lens/reflector units. H4 is the old standard European headlamp bulb. H5 is the newer DOT-approved version. They are not interchangeable - you must get the type that your lens/reflector unit uses. The connectors are different for the H4 and H5 bulbs, but the H4 connector is the same as the standard USA 7" sealed beam bulbs.
With a little effort, you can put any of the above units into any 928.
BTW - Fingerprints can drastically shorten the life of any of the peanut-sized quartz halogen bulbs.
Wally Plumley
928 Specialists
