PDI Big Boss Paccar MX13 Exhaust Manifold | 2010-2013Available for: Paccar MX13 Gen 1 Model Year 2010 2013 Key Benefits 20% average airflow increase in key areas Up to 100 degree cooler 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. Big Boss Exhaust