The horsepower for a 1997 Chevrolet K1500 with a 350 cubic inch (5.7L) engine varied slightly depending on the specific configuration and whether it was a TBI (Throttle Body Injection) or Vortec engine.
Generally, you'll find the horsepower rating to be in the range of 230-255 horsepower. You need to check the vehicle's sticker or documentation to find the exact rating for that particular truck.