Pontiac Chieftain high beam and low beam headlight bulb sizes include H5001, H5006, H6024, and H6006 specifications for this model. The replacement chart covers vehicle production years spanning 1950 to 1958 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 Pontiac Chieftain uses three distinct sealed beam formats across its model years: the H6006 rectangular unit, the H6024 round unit, and the H5001 and H5006 round units, all operating at 12 volts and conforming to ANSI standards recognized in both the United States and Canada.
The H6006 is a 5x7-inch rectangular sealed beam unit and serves as both the high beam and low beam headlight on the Chieftain for model years 1950-1954. Because it handles both functions in a single unit, the same part number applies to both beam positions during those years.
For 1955-1957, the Chieftain uses the H6024, a 7-inch round sealed beam unit, for both the high beam and low beam positions. As with the H6006, a single part number covers both functions across those three model years.
The 1958 Chieftain departs from the single-unit approach used in prior years by specifying different bulb sizes for the high and low beam positions. The high beam uses the H5001, a 4-inch square sealed beam unit, while the low beam uses the H5006, a 5.75-inch round sealed beam unit.
All four bulb types found in these specifications are sealed beam units, meaning the lens, reflector, and filament are fused into a single assembly. When a filament fails, the entire sealed unit requires replacement rather than an internal bulb.
The H5001 and H5006 used in the 1958 model year are not interchangeable with each other or with the H6024 and H6006 units from earlier years, as each has a distinct physical format: square versus round, and differing sizes.
The shift from the H6006 rectangular format in 1950-1954 to the H6024 round format in 1955-1957 reflects a change in headlight housing design, as the physical format of a sealed beam unit is determined by the housing it is designed to fit.
Because all units in these specifications are sealed beams rather than bulb-and-housing assemblies, fitment is governed by the physical format of the sealed beam itself, and substituting a unit of a different format would require a corresponding change to the headlight housing.