6.4L Power Stroke OE exhaust issues are not an 'if' but a 'when'. Prevent these issues and streamline exhaust flow from the head to your turbo inlet with BD's stronger and better flowing Exhaust Manifold & Up-Pipe Kit. Factory up-pipes are prone to failure due to age and heat cycling causing leaking exhaust, slower turbo spool, as well as additional exhaust noise and soot buildup. BD's larger diameter 304 stainless steel mandrel bent up-pipes with internally shielded expansion bellows, are designed to minimize restriction to the turbo and improve exhaust velocity and turbo response time. The BD Up-Pipes are a durable, longer-life replacement for the common Power Stoke problems as well as the perfect complimentary upgrade when replacing a turbo, manifolds, or other engine or transmission repairs. The 6.4L exhaust manifold set is crafted with a heavy duty 0.25" thick-walled Hi-Silicon ductile casting, this makes these manifolds thicker to combat cracking due to high exhaust temperatures. To maximize exhaust flow, computational fluid dynamics were used to optimize flow and exhaust port geometry. BD's exhaust manifold set is the perfect replacement for reliability, performance and peace of mind.