The BLOX Racing Power Intake Manifold features a larger plenum and longer runners which significantly increases the engine’s incoming airflow and volume compared to the factory and some other aftermarket units. Each intake manifold has been balanced, pressure tested and tuned to create more usable horsepower across a wider RPM range.The BLOX Racing Version 3 intake manifolds feature a pre-drilled plenum that accommodates the surface-mount vacuum block without the need of drilling or other modifications. The BLOX Racing surface-mount vacuum provides an easy and clean installation when additional sources of vacuum are required.bSurface-mount block is sold separately.