Designed for competition 396-502 big-block Chevys with rectangular-port heads. Victor Jr. intakes have been optimized with the flow characteristics of an 850cfm 4150 carburetor. Features include extended runner dividers, smaller plenum chambers and unique runner design for better 60 foot times and max power from 3500 to 7500 rpm. This manifold is cast with 3/8" more material in the corners of the ports for a final radius of 3/4". This extra material allows for custom port matching for use with various cylinder head applications.