GMC 300 high beam and low beam headlight bulbs utilize H6024, H5001, H6006, and H5006 bulb sizes across multiple configurations. The replacement chart covers vehicle production years spanning 1951 to 1959 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 H6006 is the most consistently used sealed beam type across the GMC 300's headlight specifications, appearing in both high beam and low beam positions for the 1951-1955 model years. It is a 5x7-inch rectangular sealed beam unit rated at 12V and conforms to ANSI standards applicable in the US and Canada.
All four bulb types listed in these specifications, H6024, H5001, H6006, and H5006, are sealed beam units rather than bulbs with replaceable filaments. In each case, the entire sealed unit is replaced when the light fails.
The GMC 300 for 1956-1957 used the H6024 for both high beam and low beam positions. This is a 7-inch round sealed beam unit operating at 12V, also conforming to ANSI standards for the US and Canada.
For 1958-1959, the GMC 300 headlight fitment depended on the number of headlamps installed. Two-headlamp configurations used the H6024 for both beams, while four-headlamp configurations split the duties between the H5001 for high beam and the H5006 for low beam.
The H5001 and H5006 are physically distinct sealed beam units. The H5001 is a 4-inch square unit, while the H5006 is a 5.75-inch round unit. Both operate at 12V and are not interchangeable with each other despite appearing together in the same four-headlamp system.
The H6024 and H6006 are also physically distinct and not interchangeable. The H6024 is a 7-inch round unit, whereas the H6006 is a 5x7-inch rectangular unit, and each corresponds to a different era of fitment within these specifications.