The Pontiac J2000 headlight bulb specifications include H4651 and H6054 sizes for high beam operation and H4652 and H6054 sizes for low beam operation, with the bulb size chart covering replacement data from 1982 to 1983.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The Pontiac J2000 uses sealed beam headlight units across its 1982-1983 model years, meaning the entire lens-and-filament assembly is replaced as one unit rather than swapping an internal bulb.
The H4651 and H4652 are both 4x6-inch rectangular sealed beam units operating at 12V and conforming to ANSI standards recognized in the US and Canada. The H4652 is a variant of the H4651, with the two types serving different beam functions rather than being interchangeable with each other.
The H4651 is designated for the high beam headlight position on the 1983 J2000, while the H4652 fills the low beam position that same year. Substituting one for the other would place the wrong beam pattern in the wrong housing.
The H6054 is a 5x7-inch rectangular sealed beam unit, also rated at 12V and ANSI-compliant. It is physically larger than the H4651 and H4652 units, which means the two size families are not interchangeable.
The 1982 Pontiac J2000 uses the H6054 for both high beam and low beam positions, with beam function determined by which filament inside the unit is activated rather than by separate part numbers.
The shift from H6054 in 1982 to the H4651 and H4652 pairing in 1983 reflects a change in headlight housing size between those two model years, making cross-year unit substitution incompatible without modification.