The GM LS Gen IV engine dominates the high-performance V-8 market and is the most popular powerplant for engine swap projects. In stock trim, the Gen IV engines produce class-leading horsepower. The Gen IV’s rectangular-port heads flow far more air/fuel than the Gen III cathedral-port heads. However, with the right combination of modification procedures and performance parts, you can unlock the performance potential of the Gen IV engines and reach almost any performance target. Engine building and LS expert Mike Mavrigian guides readers through the best products and modification procedures to achieve maximum performance for a variety of applications. To make more horsepower, you need to flow more air and fuel into the engine; therefore, how to select the industry-leading aftermarket heads and port the stock heads for superior performance are comprehensively covered. The cam controls all major timing events in the engine, so determining the best cam for your engine package and performance goals is revealed. But these are just a few aspects of high-performance Gen IV engine building. Installing nitrous oxide or supercharger systems and bolting on cold-air intakes, aftermarket ignition controls, headers, and exhaust system parts are all covered in detail. The foundation of any engine build is the block, and crucial guidance for modifying stock blocks and aftermarket block upgrade advice is provided. Crankshafts, pistons and rods, valvetrain, oiling systems, intakes and fuel injection, cooling systems are all covered so you can build a complete high-performance package. A massive amount of aftermarket parts is available for the Gen IV platform, and this new book provides guidance and instructions for extracting top-performance from these engines.