Single Plane EFI Split-Design Race Intake Manifold- GM LS3/L92- Black EFI Single Plane Split-Design Race Intake Manifold Fits All GM LS Gen III or IV Engines Equipped with LS3/L92 Cylinder Heads Holley? As Cast Runner Cross Sectional Area 4. 5 in2 at the runner entry tapered to 3. 2 in2 at the flange exit The Ls Race single plane intake manifold was designed for hi performance racing engine applications, 5. 3 to 6. 2+ liter displacement, and maximum engine speeds of 6000 7000 rpm, depending on the engine combination. This single plane design provides optimal performance across the RPM spectrum while providing maximum performance up to 7000 rpm. ?