You can find this information in a few ways:
* Ford's Official Specifications: The most reliable source would be Ford's own specifications for that year and model. You might find this information in old Ford brochures, owner's manuals (often available online through sites like eBay or used parts websites), or archived Ford websites. However, finding exact original documentation can be challenging.
* Automotive Repair Manuals: Repair manuals like those from Haynes or Chilton often list engine specifications, including horsepower and torque.
* Online Automotive Databases: Websites like Edmunds.com or Kelley Blue Book (KBB.com) *sometimes* include historical data, but it's not always comprehensive or accurate for older vehicles.
* Automotive Encyclopedia Websites: Websites dedicated to automotive history and specifications might have this data.
Keep in mind that the horsepower rating can vary slightly depending on the exact configuration of the truck (e.g., transmission type, optional equipment) and the method used to measure it. 230 horsepower is a reasonable and commonly cited figure for that engine in that year's F-250.