This new manifold for Big-Block Chevy is a variation of our Victor 454-R manifold 350-2907 with a 3/4'' radius in the ports, producing a port exit compatible with current large oval port heads such as the Edelbrock/Musi Victor 24 deg CNC head 350-61409. It shares the performance attributes of the original 350-2907, giving excellent on-track performance on 502 cid and smaller engines. It can be ported to fit a wider variety of cylinder head shapes and locations, making it especially suitable for use with custom CNC ported heads.