Tuning For 4500, 5500, and 6500 Duramax-Powered Silverado

Tuning your L5D Duramax just got a lot easier with Calibrated Power. Find out how you can get an additional 125-plus horsepower.Tuning your L5D Duramax just got a lot easier with Calibrated Power. Find out how you can get an additional 125-plus horsepower.