The 50 series "Big Block" muffler is our largest muffler for tow vehicles, trucks, large Sport utilities and Recreational Vehicles. This muffler is made for more than just big cubic inch engine applications. It has a very large H-Chamber to reduce interior resonance in large cab areas of vehicles and enough case volume to handle engines under heavy loads. Constructed of 16 gauge aluminized steel and fully mig-welded for maximum durability.