The Maserati 425 high beam headlight uses an H4651 bulb size while low beam headlights require either H4652 or H4656 bulb sizes. The replacement chart covers vehicle production spanning 1986 to 1987.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The H4651, H4652, and H4656 are all ANSI-standardized sealed beam units designed for the North American market, operating at 12 volts and housed in a 4x6-inch rectangular form factor.
Sealed beam units of this type contain the filament, reflector, and lens fused into a single glass assembly, which means the entire unit is replaced rather than an individual bulb.
The Maserati 425 uses the H4651 for the high beam headlight position across both the 1986 and 1987 model years.
The low beam headlight position differs between model years: the 1987 model uses the H4652, while the 1986 model uses the H4656.
Although the H4652 is a variant of the H4651 and shares the same 4x6-inch rectangular sealed beam format, the two are specified for different lighting positions and are not interchangeable within the same vehicle.
The H4656 and H4652 occupy the same low beam position across different model years but are distinct part numbers, and substituting one for the other without confirming compatibility would be inadvisable.