Lincoln Versailles high beam headlight bulbs use H4651 size while low beam headlight bulbs use H4656 or H4652 size. The replacement chart covers vehicle production years spanning 1977 to 1980 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 H4651, H4652, and H4656 are all ANSI-standardized sealed beam units used across the North American market, operating at 12 volts. Each type takes the form of a 4x6-inch rectangular sealed beam, meaning the lens, reflector, and filament are fused into a single non-serviceable assembly. When the filament fails, the entire unit requires replacement rather than an internal bulb swap.
The Lincoln Versailles uses the H4651 for the high beam headlight position across all four model years covered (1977-1980), making it the most consistent fitment in these specifications.
The low beam headlight position on the Lincoln Versailles shows a split fitment across the covered years. The 1979-1978 model years use the H4652, while the 1977 and 1980 model years use the H4656.
The H4652 is a variant of the H4651 within the same 4x6-inch rectangular sealed beam family. Despite their shared physical format and ANSI classification, the H4651 and H4652 carry distinct part designations and are not listed as interchangeable in these specifications.
The H4656 and H4651 share the same physical format and voltage rating but occupy different positions in the headlight system. The H4651 is designated for high beam use, while the H4656 appears exclusively in the low beam position, reflecting differences in beam pattern or filament output between the two types.
Because all three bulb types are sealed beam units, fitment is governed by the physical housing size and ANSI designation rather than by a separate bulb socket or base type. Substituting one sealed beam type for another in a position where it is not specified risks incorrect beam alignment or light output.