Pontiac Firebird Headlight Bulb Size

Additional Notes

• Every headlight bulb size listed across all model years of the Pontiac Firebird is a sealed beam unit, meaning the entire lens-and-filament assembly is replaced as one piece rather than a separate bulb being swapped within a housing.
• All sealed beam types specified for the Firebird operate at 12 volts and conform to ANSI standards recognized in both the United States and Canada.
• The H4666 sealed beam is the specified type for both high and low beam positions on the Pontiac Firebird for model years 1991-1997, making it the single unit that serves dual functions in that headlight assembly.
• The H6054 is a 5x7-inch rectangular sealed beam unit used in both the high and low beam positions for the 1982-1990 model years, and it is one of the most widely used sealed beam formats in the North American automotive market.
• For the 1977-1981 model years, the high beam and low beam positions use different bulb types despite sharing the same 4x6-inch rectangular sealed beam format. The high beam uses the H4651, while the low beam uses either the H4652 or H4656, both of which are variants within the same physical size class.
• The 1977 Firebird low beam position specifies the H4656, whereas the 1978-1981 low beam position specifies the H4652, which is described as a variant of the H4651 high beam unit used across all five of those years.
• The H6024, a 7-inch round sealed beam unit, is specified for both beam positions on the 1970-1976 model years, representing the round sealed beam format that was standard across much of the American automotive industry during that period.
• The 1967-1969 model years use two distinct round sealed beam sizes: the H5001, a 4-inch square sealed beam for the high beam, and the H5006, a 5.75-inch round sealed beam for the low beam, reflecting a quad headlight arrangement that separates the two functions into physically different units.