Edelbrock Part # 28540 BV3 CNC intake manifold is designed and has been CNC port matched for use with Edelbrock BV3 cylinder heads which feature a unique symmetrical port layout for the 4.84" bore spacing big-block Chevrolet applications. This manifold features a spider style single-plane design with efficient runners that are engineered to deliver peak performance across a wide range of applications. The manifold has a lengthened plenum and a narrowed runner design to deliver equal length runners. This manifold is also the first in the Big Victor Series to feature Edelbrock's unique two-piece design. This unique design simplifies and reduces time in applications that require CNC porting. The manifold is cast in two separate pieces, allowing them to be taken apart for better porting access and then they can be bolted back together while maintaining a perfect match. Each piece has a precision machined o-ring groove to ensure a proper seal. High quality bolts and washers are supplied. The manifold also has a matching valley plate with the proper flange thickness (sold separately). This unique valley plate features a highly efficient integrated water distribution system, reducing the need for external plumbing.