FAST 146302B LSXR 102mm Intake Manifold - LS1, LS2, LS6LSXRCathedral Port Heads (LS1, LS2, LS6) FAST engineers teamed up with airflow specialists at RHS to develop polymer intake manifolds for GM LS based engines. Testing on a near stock LS7 engine with a Big Mouth 102mm Throttle Body produced gains of 16+ horsepower, and 26+ rear wheel horsepower on a 500c. i. engine. The LSXR 102mm Intake Manifold features a revolutionary new modular design that allows fast and easy disassembly and features the ability