Designed for competition 396-502 big-block Chevys. #2902 fits rectangular-port heads and #2904 fits large oval-port heads (1975 & earlier). These intakes are designed to optimize the flow characteristics of an 850 cfm standard flange carb. Features include extended runner dividers, smaller plenum chambers and unique runner design for better 60 foot times and max power from 3000 to 7500 rpm. These manifolds are especially suited to 502 c.i.d. and smaller competition engines. #29020 is a single plane 4150 flange competition manifold designed to fit standard deck blocks from 1965 to present. This new 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. It is designed to be matched with our Edelbrock/Musi Victor 24 degree Pro-Port CNC heads #61419 or #61409 for 950+ hp out-of-the-box potential! Victor Jr. 454-R #2902 will fit Edelbrock Victor race heads #77609, and Victor 24 degree #77409, #77459, #77429, #77479, #77489. Victor EFI also available with electronic fuel injector bosses, see Street & Competition EFI Manifolds.