These custom size taller, straight back CMI E-Top are a superior long tube header designed for both racing or any high-performance application. These leaned, taller headers are commonly used in custom or staggered setup Mercury 525-700 series motors. These headers feature the CMI Flex Flare Tailpipe Connection. For big-block applications, where maximum scavenging and horsepower are required, CMI Sport Tube headers deliver peak performance and power from naturally aspirated engines. This version has a polished elbow and satin primaries with the rubber distribution tube.