White WHM headlight bulbs utilize 9004 and H4651 sizes for high beam applications and 9004 and H4656 sizes for low beam applications. The replacement chart covers 1981 through 1987 vehicle production years with corresponding bulb size specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 9004 is a dual-filament halogen bulb rated at 12V with a wattage split of 65W for high beam and 45W for low beam, mounted on a P29t base. Its dual-filament design allows a single bulb to serve both high and low beam functions within one housing.
Because the 9004 handles both high and low beam outputs, the White WHM lists it under both the High Beam and Low Beam Headlight categories for conventional headlight configurations across the 1981-1987 model years covered in the specifications.
The H4651 and H4656 are 4x6-inch rectangular sealed beam units operating at 12V. Unlike the 9004, neither contains a replaceable filament assembly; the entire sealed unit is replaced when it fails.
The H4651 is designated for the high beam position, while the H4656 fills the low beam position on non-conventional headlight systems. Although both share the same physical 4x6-inch rectangular format, they are not interchangeable between positions.
All three bulb types, the 9004, H4651, and H4656, conform to ANSI standards recognized in both the United States and Canada, placing them within a standardized sizing and performance framework common to North American vehicle lighting.
The specifications split White WHM headlight fitment into two distinct system types: conventional, which uses the 9004 for both beam positions, and non-conventional, which uses the H4651 for high beam and the H4656 for low beam. Selecting the wrong type for the installed system would result in an incompatible fitment.