Grand Rock Co. Inc. is a manufacturer of diesel truck exhaust systems located in Painesville, Ohio. The company offers original equipment manufacturer (OEM) replacement parts for Kenworth, Peterbilt, Mack, Ford, Western Star, International, Volvo and Sterling. Grand Rock Co. Inc. also specializes in custom exhaust parts and mufflers. The company is the exclusive aftermarket distributor of Westfalia products in the United States. Grand Rock Co. Inc. has a state-of-the-art flexible exhaust hose and preformed seal clamp systems. In addition, the company fabricates from 3" to 7" dia tubing in plain, aluminized and chrome as well as it can powder and ceramic coat parts.