Keep in mind that this is just an estimate. Actual mileage will depend on factors like:
* Engine size: A larger engine will generally get worse gas mileage.
* Transmission type: Automatic transmissions tend to use slightly more fuel than manuals (though the Caprice was almost certainly automatic).
* Driving style: Aggressive acceleration and high speeds significantly reduce fuel economy.
* Vehicle condition: Proper maintenance (tune-ups, etc.) impacts MPG.
* Terrain: Driving uphill or in stop-and-go traffic will lower your mileage.
To get a more precise estimate, you would need to specify the exact engine (e.g., 267ci V6, 305ci V8, 350ci V8) and transmission type.