PPE 116120000 REPLACEMENT UP-PIPES 2001 - 2004 GM LB7The PPE 116120000 Replacement Up Pipes for your 2001 2004 GM 6. 6L LB7 Duramax increase flow, and reliability. Even a stock Duramax can produce high temperatures and pressures that cause OEM up pipes eventually fail from constant temperature and pressure fluctuation. PPE has taken the OEM replacement to a new level. PPE OEM Up Pipes allow 53% greater flow over stock, and are a direct bolt on to your factory manifolds. But unlike factory parts, PPE OEM