Many people modify their Harley-Davidson engines—and find the results disappointing. What they might not know—and what this book teaches—is that emphasizing horsepower over torque, the usual approach, makes for a difficult ride. Author Bill Rook has spent decades perfecting the art of building torque-monster V-twin Harley engines. Here he brings that experience to bear, guiding motorcycle enthusiasts through the modifications that make a bike not just fast but comfortable to ride. With clear, step-by-step instructions, his book shows readers how to get high performance out of their Harleys—and enjoy them, too.