To be absolutely certain, I highly recommend:
* Consulting your owner's manual: This is the best source of information specific to your vehicle.
* Looking at a repair manual specific to a 1980 Corvette: This will have diagrams and detailed instructions.
* Searching online for pictures of a 1980 Corvette engine bay: Comparing images to your car will help you locate the reservoir.
Caution: Always check the fluid level when the engine is cold and the car is level. Never overfill the reservoir.