White WCM Headlight Bulb Size

The White WCM headlight bulb size specifications include high beam options of 9004, H6024, and H4651, along with low beam alternatives of 9004, H6024, and H4656. The replacement chart covers 1981 through 1988 vehicle production years with corresponding bulb size data.

The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.

High Beam Headlight

Years	Bulb Size
1988	9004 (With Composite Headlamps)
1988	H6024 (With Sealed Beam Headlamps)
1981-1987	9004 (Conventional)
1981-1987	H4651 (Except Conventional)

Low Beam Headlight

Years	Bulb Size
1988	9004 (With Composite Headlamps)
1988	H6024 (With Sealed Beam Headlamps)
1981-1987	9004 (Conventional)
1981-1987	H4656 (Except Conventional)

Bulb Specifications

Description	Bulb Size
ANSI standard (US & Canada). Dual-filament halogen bulb with P29t base. 12V, 65W/45W.	9004
ANSI standard (US & Canada). 7-inch round sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H6024
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4651
ANSI standard (US & Canada). 4x6-inch rectangular sealed beam unit. Not a replaceable bulb — the entire unit is replaced. 12V.	H4656

Other Locations

Additional Notes

The 9004 bulb is a dual-filament halogen type operating at 12V with a P29t base and a power rating of 65W on the high beam filament and 45W on the low beam filament. Its dual-filament design allows a single bulb to serve both high and low beam functions within a composite headlamp assembly.
The White WCM uses the 9004 bulb for both high and low beam positions in conventional headlamp configurations across the 1981-1988 model years. Because both beam positions share the same bulb type in this configuration, only one bulb part number is required per headlamp housing.
The H4651 and H4656 are both 4x6-inch rectangular sealed beam units operating at 12V under the ANSI standard applicable to the US and Canada. In sealed beam units, the lens, reflector, and filament form a single sealed assembly, meaning the entire unit is replaced rather than an internal bulb.
On the White WCM for 1981-1987, non-conventional headlamp configurations use the H4651 for the high beam position and the H4656 for the low beam position. Although both are 4x6-inch rectangular sealed beam units, they are not interchangeable between beam positions.
The H6024 is a 7-inch round sealed beam unit operating at 12V. It appears exclusively on the 1988 White WCM in configurations equipped with sealed beam headlamps, covering both the high and low beam positions.
The 1988 model year introduced a composite headlamp option, which uses the 9004 bulb. This represents a structural departure from sealed beam technology, as composite headlamps retain a permanent housing while allowing the internal bulb to be replaced independently.
The H4651 and H4656 sealed beam units conform to ANSI standards shared across the US and Canadian markets. Fitment is determined by beam position rather than by any difference in physical size, as both units occupy the same 4x6-inch rectangular form factor.
The 9004 bulb also conforms to ANSI standards for the US and Canadian markets. Its P29t base is a specific connector type, and substituting a bulb with a different base would be physically incompatible with the composite headlamp socket on the White WCM.