For 3500 to 8000 PRM high performance engines. Extended constant cross-section of runners. Great mid-range torque for short track power. Improved throttle response for 60 foot times. Direct line of sight flow path maximizes flow. Designed for 23 degree standard port heads. About 50 inches taller than Victor Jr. PN(2975). Runners have a 2.80 square inch cross section. Product Features:For 3500 to 8000 RPM High-Performance EnginesExtended Constant Cross-Section of RunnersGreat Mid-Range Torque For Short Track PowerImproved Throttle Response For 60 ft. TimesDirect Line of Sight Flow Path Maximizes FlowDesigned for 23 degree Standard Port HeadsAbout .50 in. Taller Than Victor Jr PN[2975]Runners Have a 2.80 square in. Cross Section