Chevy Small Bock Gen 1, 400ci externally balancedEngine Harmonic BalancerFluidamprFluidampr Performance DamperHarmonic BalancerHarmonic Balancer - Fluidampr - External Balance - 26 oz - Steel - Black Zinc - SFI 18.1 - 7-1/4 in O.D. - Small Block Chevy - EachHarmonic Balancer - Fluidampr - Small Block Chevy - Eachharmonic, Balancer, balancer, fluidamprProtect your engine. A Fluidampr performance damper provides premium, broad range control of destructive crankshaft torsional vibration for optimum performance and durability. Install as an upgrade to OEM elastomer style harmonic balancer, when horsepower is gained, or when rotating assembly parts change to reduce wear on critical internal engine components. Features high quality, long lasting viscous silicone damper technology with precision CNC machined and computer balanced high-grade steel components. No tuning or maintenance required. SFI 18.1 approved, race proven for over 25 years. Made in the USA.