These Hooker BlackHeart LT Turbo Exhaust Manifolds are the simple solution for adding a turbo to your muscle car. They are made from High-Silicon-Moly ductile iron, have a natural cast finish and are much more durable than fabricated headers. A turbo cross-over tube is available for manifold connection (sold separately). A universal cross-over component kit is also available for custom applications (requires fabrication & welding). These manifolds are part of a full line of LT swap components (i.e. motor mounts, swap oil pan, and accessory drive systems) & provide the building blocks needed to complete a custom turbo system for your GM LT engine Patent - www.holley.com/patents/