PDI Big Boss CAT 3406E/C15/C16 Low Mount Exhaust ManifoldAvailable for: 1994 2004 CAT 3406E, C15, C16 Engines CAT manifold CARB EO# D773 2 Key Benefits 20% increase in airflow over stock 75 100 degree cooling of EGTs Made in the USA Warranty: 2 Year Unlimited Mile Warranty We have designed our exhaust manifolds to maximize the exhaust air flow to reduce turbo lag time and cool exhaust temperatures. In the design of the manifold each port is analyzed and tested to provide a balanced flow to the turbocharger.