This LSXRT™ Intake Manifold gives LS3 engines with rectangle-port cylinder heads even more plenum volume for all-out racing. Best suited for high-RPM race engines, this manifold creates proven gains of 30+ horsepower over the FAST® LS3 Street Manifold at high RPM. The raised 102mm throttle body location optimizes the larger, less restrictive High HP runner design, creating more power. It also clears truck drive accessories.