What is the horsepower rating for a 1978 440?

The horsepower rating for a 1978 440 engine depended heavily on the application (the car it was in). There wasn't one single horsepower figure. The output varied significantly based on the vehicle and the specific carburetor and other options. You'll find numbers ranging from approximately 220 hp to over 260 hp depending on the exact configuration. To get the precise horsepower for a specific 1978 vehicle with a 440, you'd need to check the original vehicle's specifications.