Compatible with LS1/LS2/LS6 Carbureted with Cast Finish; The new Holley Single-Plane Race intake manifold is designed with maximum performance in mind. Featured is a two-piece split design that provides access for all levels of porting and modification. With shoulder bolt locators and O-ring seal, disassembly & reassembly is simple and precise. The manifold with AN-8 fuel rails fits GM LS Gen III engines with cathedral port heads and has a 4500 Dominator style carb flange for carburetors, EFI throttle bodies, or EFI throttle body elbows, and is configured with a LS MAP sensor port along with other NPT plenum vacuum or air-temp sensor ports.