GMC Truck high and low beam headlight bulbs utilize H6024 and H6006 size specifications across both lighting functions. The replacement chart covers 1950 through 1957 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.
The GMC Truck uses two sealed beam headlight types across the 1950-1957 model years: the H6006 and the H6024, both of which conform to ANSI standards recognized in the United States and Canada.
The H6006 is a 5x7-inch rectangular sealed beam unit operating at 12V. Because it is a sealed beam design, the entire unit is replaced rather than an internal filament or capsule.
The H6024 is a 7-inch round sealed beam unit, also rated at 12V and also requiring full unit replacement rather than bulb-only service.
The GMC Truck (1950-1955) uses the H6006 for both high beam and low beam headlight positions, meaning a single bulb type serves both functions across those years.
For the 1956-1957 model years, both the high beam and low beam positions shift to the H6024, replacing the rectangular H6006 with a round sealed beam unit.
The rectangular H6006 and the round H6024 are not interchangeable. Their differing form factors and mounting configurations make one a direct substitute for the other only within the same fitment group.
Because both the H6006 and H6024 are sealed beam units, the lens, reflector, and filament are fused into a single assembly, which was the dominant headlight construction standard for this era of vehicle production.
The 12V operating voltage is consistent across both the H6006 and H6024, aligning with the 12-volt electrical systems that became standard in American vehicles during the 1950s.