Protect your engine. Modifications can compromise your stock harmonic balancer. Install a Fluidampr performance damper early for best durability. Superior viscous damper design controls harmful torsional vibration across the entire rpm range. Reduce wear on engine components. Reduce risk of crankshaft failure. Improve timing. Unleash lost torque and horsepower. Precision CNC machined and balanced high-grade steel components. Corrosion resistant black zinc finish with engraved timing marks. No maintenance required. Trusted by leading engine builders worldwide. SFI 18.1 certified. Made in USA. NOTE: 6 bolt holes evenly space pulley pattern. Some older B series may require stock pulley to be re-drilled. Harmonic Balancer - Fluidampr - Mopar Big Block - B/RB/426 Hemi - Steel - Black Zinc Chromate - 7-1/4" dia - 11.8 lbs - SFI 18.1 - Made in USA - Each Chrysler B/RB 350, 361, 383, 400, 413, 426, 440, 426 HEMI. Internal balance.