The new Holley Single-Plane Race intake manifold were designed with performance in mind. They feature a race bred, two piece split feature that was previously only found on the most expensive race intakes. The manifold will fit GM LS Gen III engines with LS3/L92 heads and are intended for 4150 style square bore flanged carburetors or throttle body EFI. 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. The Holley LS Race manifold incorporates a split feature, which allows disassembly of the intake for direct access to internal plenum and port surfaces, making custom porting and matching a snap. With shoulder bolt locators and O-ring seal, reassembly is simple and precise. Technical Data:  A-B Height – 7.25″ (0° carb flange angle)  Port Size- 2.59″ Height x 1.28″ Wide  Carburetor Flange – Standard 4150 for up to 1-3/4″ diameter throttle bores  As-Cast Runner Cross-Sectional Area – 4.5 in² at the runner entry tapered to 3.2 in² at the flange exit