Choose the Right DD15 Engine for Your Truck & Heavy Loads Choosing the right DD15 engine can make a big difference in truck performance, fuel economy, and hauling capability. Learn how DD15 horsepower and torque ratings compare, what the 400–505 HP options mean, and how to choose the right rating for your truck, loads, and routes. To learn more, click the link to learn about the DD15 Engine. https://hdengines.com/blogs/news/detroit-dd15-horsepower-torque-ratings