Harmonic Damper SFI BBM B/RB Int Balance

The Harmonic Damper SFI BBM B/RB Int Balance from PRW Industries is engineered for serious Mopar B and RB-series engine builders who demand reliability under extreme conditions. This racing-grade harmonic balancer is purpose-built for 426 Hemi applications and other classic big-block Chrysler powerplants. As a mechanic who has assembled countless high-performance builds, you know that crankshaft harmonics are non-negotiable—uncontrolled vibration leads to bearing wear, seal failure, and catastrophic engine damage, especially in forced-induction or high-RPM applications.

This damper features a 7.30-inch outer diameter with internal balance geometry, allowing it to work seamlessly with internally balanced crankshafts without requiring external weights. The steel construction with black paint finish provides durability and corrosion resistance in both street and strip environments. Internal balancing eliminates the asymmetric weight distribution of external-balance designs, reducing vibration amplitude across the RPM band and extending component lifespan. The SFI certification ensures this unit meets Snore Facility Institute standards for racing safety, a critical requirement for competition vehicles and high-output street builds where crankshaft failure risk is elevated.

Compatibility is limited to internally balanced Mopar B and RB-series engines, including the legendary 426 Hemi, making this the correct choice if your crank is already internally balanced. Installation requires removing the crankshaft pulley and damper bolt; standard harmonic balancer removal tools and a timing mark reference will get you dialed in. Weighing 9.61 pounds, this damper integrates with stock and aftermarket accessory drives. Whether you're freshening a vintage drag engine, building a street-strip 440, or restoring a legendary Mopar muscle car, this SFI-certified harmonic balancer delivers the vibration control and durability that separates good builds from bulletproof ones.