Chevrolet Biscayne Clock Light Bulb Size

Additional Notes

• The Chevrolet Biscayne clock light specifications cover model years 1958 through 1970, with four distinct bulb types used across that span: the 194, 1895, 1816, and 57, along with the 257 as an additional fitment for the 1960 model year.
• The 194 is a T10 miniature wedge bulb rated at 12V and 3.78W under the ANSI standard. It is the specified clock light bulb for the Biscayne across the 1968-1970 model years.
• The 1895 is a T5 miniature wedge bulb rated at 12V and 0.9W. At 0.9W, it draws notably less power than the other wedge types listed in these specifications. It is the specified fitment for the 1964-1967 model years.
• The 1816 is a T3.25 miniature wedge bulb rated at 12V and 4W, making it the highest-wattage bulb among the wedge-base types in these specifications. It is the specified fitment for the 1961-1963 model years.
• The 57 is a single-filament bulb with a BA9s bayonet base, rated at 12V and 1W. It is specified for the 1958 and 1959 model years, and also carries over as one of two specified fitments for the 1960 model year.
• The 1960 Chevrolet Biscayne is the only model year in these specifications to list two clock light bulb sizes simultaneously, with both the 57 and the 257 noted as applicable fitments.
• The 257 is a festoon or BA9s base instrument bulb rated at 12V and 2W. It shares the BA9s base type with the 57 but operates at twice the wattage, which means the two are not electrically interchangeable despite the shared base format.
• The three wedge-base bulb types (194, 1895, and 1816) are physically non-interchangeable with one another, as each occupies a different T-series envelope size, and substituting one for another would result in an incorrect fit within the clock housing.