Plymouth PB300 high beam headlight bulbs use H4651 or H6024 size, while low beam headlight bulbs use H4652, H4656, or H6024 size. The replacement chart covers 1975 to 1980 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 H6024 is a 7-inch round sealed beam unit operating at 12V and conforming to ANSI standards for the US and Canadian markets. It serves as both the high beam and low beam headlight across the Plymouth PB300 model years 1975-1978, making it the most consistently used bulb type in these specifications.
All four bulb types listed, H4651, H6024, H4652, and H4656, are sealed beam units, meaning the lens, reflector, and filament are fused into a single assembly. Replacement requires swapping the entire unit rather than an internal bulb.
The 1979-1980 Plymouth PB300 high beam headlight uses the H4651, a 4x6-inch rectangular sealed beam unit rated at 12V and built to ANSI standards.
The low beam headlight specification for the PB300 differs between 1979 and 1980 despite both years sharing the same H4651 high beam. The 1980 model year uses the H4652, while 1979 uses the H4656, both of which are 4x6-inch rectangular sealed beam units at 12V.
The H4652 is described as a variant of the H4651. Although both share the same 4x6-inch rectangular sealed beam format and 12V rating, they are designated for different functions and are not listed as interchangeable within these specifications.
The transition from the 7-inch round H6024 format to the 4x6-inch rectangular format occurred between the 1978 and 1979 model years for the PB300, affecting both the high beam and low beam positions.