Chevrolet Nova brake bulb sizes include 1157 and 1156 bulb configurations, with center high mount stop light applications utilizing 1156 and 1157 sizes. The replacement chart covers vehicle production years spanning 1969 to 1988 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 1157 is a dual-filament bulb operating at 12V with a 21W high filament and a 5W low filament, mounted on a BAY15d bayonet base. The BAY15d base features two offset pins, which physically prevents it from being inserted in place of a single-filament socket.
The 1156 is a single-filament bulb operating at 12V at 21W, mounted on a BA15s bayonet base. The BA15s base has a single pin, making it incompatible with sockets designed for the dual-pin BAY15d base used by the 1157.
Both the 1157 and 1156 are ANSI-standardized bulbs recognized across the US and Canada, meaning their electrical and physical specifications are consistent across manufacturers producing bulbs under those designations.
The Chevrolet Nova brake light circuit used the 1157 across the 1969-1979 and 1972-1988 model years, with the single exception of 1986, which used the 1156 instead.
The 1986 Chevrolet Nova brake light specification calls for the 1156 rather than the 1157. Since the 1156 is a single-filament bulb and the 1157 is dual-filament, substituting one for the other is not straightforward and depends on the socket type installed in the vehicle.
The Center High Mount Stop Light on the Chevrolet Nova used the 1156 for the 1985, 1987, and 1988 model years, while the 1986 model year used the 1157 for that same position.
The 1986 Nova presents an inverse relationship between its brake light and Center High Mount Stop Light bulb types: the standard brake light used the 1156 while the Center High Mount Stop Light used the 1157, the opposite of the pattern seen in 1985, 1987, and 1988.
Because the 1157 and 1156 share a similar physical size and voltage rating, visual inspection alone is not a reliable method for distinguishing them. The pin configuration of the base is the definitive differentiator between the two types.