BD's new ceramic-coated heavy-duty exhaust manifolds are made to withstand high temperatures and enable smooth exhaust flow. These are ideal for truck owners replacing their manifolds due to cracks/leaks or are looking to upgrade their stock CAT 3406E/C15 turbo with a new T6 turbo. BD's exhaust manifolds are constructed of thick-walled, durable high-silicon ductile iron which with their 3-piece design will prevent cracking and help reduce future repair costs and downtime