Cast flywheels are not explosion-proof, and can be dangerous when used in high-performance applications at higher rpms. RAM billet steel flywheels are recommended as replacements for factory-cast flywheels in high-performance and racing vehicles. They're better for launching heavier drag race cars and provide better drivability in street vehicles. RAM billet steel flywheels are CNC-machined from certified materials, and friction surfaces are Blanchard-ground parallel to the crankshaft mounting flange, for minimum runout and optimum clutch engagement. These flywheels are SFI-approved.