Control the valvetrain in your modified 1998.5-2022 Dodge 5.9L Cummins with the XDP HD High Boost Valve Spring Set XD390. The XD390 Valve Spring Kit is designed to help eliminate valve float due to elevated cylinder pressures and higher boost levels. Common upgrades like aftermarket tuning and fueling and turbo upgrades can cause valve float that results in severe engine damage. Intake valves can also be blown open from added boost levels and exhaust drive pressure which allows reversion. Reversion is when exhaust gasses enter cylinder on the intake stroke, another condition that can hurt your power potential. The XD390 Valve Spring Set is ideal for the enthusiast that is running an aftermarket camshaft, upgraded or compound turbochargers, and fueling upgrades. These springs are ready to install using your factory retainers and locks. The XD390 Valve Springs have a reduced OD and will fit all 1998.5-2002 cylinder heads regardless of the casting inconsistencies.Features: Performance Valve Spring Kit Essential For Elevated Boost Levels (50 and up lbs) Specifications: Installed Height: 1.340 inch Installed Pressure: 108lbs 192lbs at .920 inch Coil Bind: .800 inch