The GMC S370 headlight bulb uses H6024 and H6006 sizes for both high and low beam applications. The replacement chart covers 1951 through 1957 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 GMC S370 used two distinct sealed beam headlight units across its 1951-1957 model years: the H6006 for 1951-1955 and the H6024 for 1956-1957.
Both the H6006 and H6024 are sealed beam units, meaning the lens, reflector, and filament are fused into a single assembly. When the filament fails, the entire unit is replaced rather than an internal bulb.
The H6006 is a 5x7-inch rectangular sealed beam unit operating at 12 volts and conforming to ANSI standards recognized in both the United States and Canada.
The H6024 is a 7-inch round sealed beam unit, also rated at 12 volts and built to the same ANSI standard applicable in the United States and Canada.
On the GMC S370, the high beam and low beam headlight positions use the same bulb size for any given model year, as both functions are served by a single sealed beam type per year.
The H6006 and H6024 are not interchangeable with each other, as they differ in physical shape and housing format, one being rectangular and the other round.