The new single plane EFI intake manifold is designed to provide a broad RPM powerband for high-performance street/strip engine applications to a maximum engine speed of 7500 RPM. The manifold is designed to work with 4150 Style Throttle body EFI systems like the Holley 4150 style flange Universal Throttle Bodies. These intake manifolds are designed to accept most stock hardware and accessory brackets, but offer performance features; like an updated plenum divider area, a 1″ shorter overall height than most single plane manifolds, and a choice of two distributor clamp locations. The isolated design of the air/fuel passages helps to increase charge air density and performance. The fuel injector bores have back-cut exits in the runners for better fuel atomization. This design points the injectors at an angle to match the intake runner airflow angle. The black coated fuel rails and rail bracket assortment are included with the manifold for any easy installation with the injectors that you choose to use for your combination. Fuel rail designed for maximum throttle lever clearance. (Injectors are not included) The 300-260 intake manifolds are designed 4150 style Throttle Body EFI applications on 1957-86 262-400cid Small Block Chevrolet engines and SBC engines equipped with 1987-91 L98 aluminum Corvette cylinder heads (non-EGR applications). Also, these manifolds will work with any SBC engine equipped with aftermarket cylinder heads, as long as they have a standard port flange opening and mounting bolt locations. Also Available: 20-86 Throttle Cable Bracket, 20-87 Kickdown Cable Bracket