The GMC F370 headlight bulb uses H6024 and H6006 sizes for both high and low beam applications, with these bulb specifications applying across the vehicle's production range. The replacement chart covers 1951 through 1957 model years and details the corresponding bulb size options for each production year.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The GMC F370 uses two sealed beam unit types across its model years: the H6024 for 1956-1957 and the H6006 for 1951-1955.
Both the H6024 and H6006 are sealed beam units, meaning the lens, reflector, and filament are fused into a single assembly. When a filament fails, the entire unit requires replacement rather than an internal bulb swap.
The H6024 is a 7-inch round sealed beam unit operating at 12V and conforming to ANSI standards recognized in both the United States and Canada.
The H6006 is a 5x7-inch rectangular sealed beam unit, also rated at 12V and built to the same ANSI standards applicable in the United States and Canada.
On the GMC F370, the high beam and low beam headlight positions share the same bulb type for each model year. Both positions use H6024 in 1956-1957 and H6006 in 1951-1955.
The shared sealed beam design for both beam positions indicates a single-unit-per-side configuration, where one sealed beam handles both high and low beam functions through separate filaments within the same assembly.
The H6024 and H6006 are not interchangeable. Their physical form factors differ, with the H6024 being round and the H6006 being rectangular, making cross-substitution between the 1951-1955 and 1956-1957 model years incompatible.