Mufflers increase fuel mileage, performance

Grand Rock has Quiet Performance mufflers available for dual-exhaust trucks. These patented, new-technology mufflers provide an average fuel mileage increase of 6.2%. The company has noted a 3% horsepower gain on dynamometer tests.

These mufflers are as quiet as stock mufflers, making them legal in all 50 states. They install inside Grand Rock's long chrome stacks, eliminating the large 10" mufflers.

Grand Rock supplies the heavy-truck market with a line of exhaust parts, ranging from 3" to 7" diameter, aluminized or chrome. For more information, contact Grand Rock, 395 Fountain Ave, Painesville OH 44077.