By the late 1990s, General Motors realized that its old Detroit Diesel engine, which had been designed 20 years earlier, was due for a major update. The Detroit Diesel engine was never intended to be a serious horsepower or torque monster. It was just a steady and reliable workhorse that made credible power, met emissions standards, and achieved decent fuel economy. As Ford and Dodge released new designs of their Power Stroke and Cummins engines, respectively, General Motors needed to follow suit. The first Duramax engine made its debut in 2001. Over the last 25 years, several versions were introduced, all displacing 6.6L and all producing ever-increasing horsepower, torque, and efficiency. As with any engine that is more than two decades old, many now need a complete overhaul. In GM 6.6L Duramax Diesel V-8 Engines: How to Rebuild and Modify , all aspects of a rebuild are covered in simple step-by-step fashion with more than 375 color photos. A brief history is provided, followed by diagnosis, engine removal, and disassembly procedures, which include the special tools that are required. Next are inspection and machine work, which are followed by reassembly and reinstallation. Finally, a performance chapter is included with commentary by Gale Banks. Whether you want to tackle this project yourself or just want to know how it all works, this guide will help you along the way.