The Chevrolet C60 front and rear turn signal bulbs utilize 1157 or 2057 size specifications depending on production year. The replacement chart covers 1960 through 1988 model years with corresponding bulb size data.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 1157 bulb is the dominant turn signal specification across the Chevrolet C60 range, appearing in both front and rear positions for the 1960-1983 and 1985-1988 model years.
The 1157 is a dual-filament bulb operating at 12V with a 21W high-filament and 5W low-filament output, mounted on a BAY15d bayonet base, and rated to the ANSI standard applicable in the US and Canada.
The 2057 bulb is specified for both the front and rear turn signal positions on the 1984 Chevrolet C60, making that model year the sole exception to the otherwise consistent 1157 fitment across the production range.
The 2057 shares the same BAY15d bayonet base and 12V operating voltage as the 1157 but draws higher wattage at 26.9W on the high filament and 8W on the low filament, making it the brighter of the two bulb types in these specifications.
Because the 1157 and 2057 share the BAY15d bayonet base, they are physically interchangeable in terms of socket fitment, though their differing wattage outputs mean they are not electrically equivalent substitutes.
The front and rear turn signal positions use identical bulb specifications for every model year in the data, meaning no asymmetry exists between the two positions across the entire production range covered.