Custom Marine has introduced header packages for the Mercury Racing 520 stern drive. CMI 520 Sport Tubes reportedly increase output by up to 48 horsepower and improve mid-range acceleration and torque. The special downturn collector improves water fill and water flow through the system and the headers have a patented Cool Collar design. The pipes are mandrel bent and formed from 316L stainless steel and come in a polished finish.
CMI says its 520 E-Top Headers increase output by up to 31 horsepower and boosts mid-range torque and acceleration. They are a direct replacement that work with existing transom outlets. The 520 E-Top headers have the patented Cool Collar design and are mandrel bent and formed from 316L stainless steel. They are available in polished and satin finish.
