If you’re looking for every last bit of intake airflow for your race-ready 400ci (6.6L) or larger LS1/LS2/LS6 cathedral port engine, look no further than Holley’s Single Plane 4500 Split-Design Race Intake Manifold. Not only do these intake manifolds provide excellent airflow, but the split design means that accessing the internal plenum for porting work is easy. These intakes are lighter than other split manifolds. There are two designs available: one for EFI that has billet fuel rails included, and one that is designed for 4500-style carburetors, EFI throttle bodies, or EFI throttle body elbows.