The FAST LSXHR intake manifolds are available for LS3 rectangular port applications, as well as LS7 raised rectangular port applications. These units are the industry's first polymer tunnel ram-style intake manifolds—and are ideal for generating maximum power in boosted and naturally aspirated engines. Order the model designed for your application. Features include: * Standard "tall" stacks are interchangeable with separately purchased "medium" and "short" stacks to find the most powerful combination * Polymer construction is lightweight and high strength to eliminate power-robbing heat soak commonly found in aluminum intake manifolds * Average 30 hp gain between 5,000 and 7,500 rpm over competitors' high-ram intake manifolds * Rated for up to 45 psi of continuous pressure * Compound fuel injector angle aims spray pattern for ideal atomization, resulting in maximum power production and superior drivability * Reversible top allows for forward- or firewall-facing throttle body installations * Two nitrous nozzle bosses per runner for clean and easy direct port system installations * 103mm throttle body opening can be ported to 105mm