Chevrolet Nova front and rear turn signal bulbs utilize 1156NA, 1156, and 1157 bulb sizes across different model configurations. The replacement chart covers 1969 through 1988 production years 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 the most frequently specified bulb across the Chevrolet Nova turn signal data, appearing in both front and rear positions across the majority of model years covered.
The 1157 is a dual-filament bulb rated at 12V with a 21W high filament and a 5W low filament, mounted on a BAY15d bayonet base, which allows it to serve both signaling and parking light functions within a single housing.
The 1156 is a single-filament bulb rated at 12V, 21W, using a BA15s bayonet base. Because it carries only one filament, it is dedicated solely to the turn signal function rather than a combined signal and running light role.
The BA15s base of the 1156 and the BAY15d base of the 1157 are not interchangeable. The BAY15d base has offset locating pins to prevent incorrect installation, so a 1156 cannot be substituted directly into a socket designed for a 1157, and vice versa.
The 1156NA and 1157NA variants are identical in electrical specification and base type to their respective standard counterparts, with the sole distinction being natural amber-tinted glass, which produces an amber output without relying on a colored lens.
The 1977 Chevrolet Nova front turn signal uses the 1157NA rather than the standard 1157, indicating that the lens for that position in that year was clear or non-amber, requiring the bulb itself to supply the amber color.
The same NA substitution is present for the 1970 Chevrolet Nova front turn signal, which also specifies the 1157NA, consistent with a clear-lens front signal assembly for that model year.
The 1988 Chevrolet Nova front turn signal specifies the 1156NA, a single-filament natural amber bulb, while the rear turn signal for the same year specifies the standard 1157, a dual-filament clear bulb, meaning the front and rear positions require different base types and filament configurations that year.
For the 1985-1986 Nova, both the front and rear turn signals share the 1156, making those the only years in the dataset where a single-filament bulb is specified for both positions simultaneously.
All four bulb types in these specifications conform to ANSI standards recognized in both the United States and Canada, placing them within a standardized sizing and performance framework common to North American automotive lighting.