BHJ Crankshaft Harmonics Study
Summary of the study: Basically BHJ did a study on the dynamics of the crankshaft Vortec 4200. What they found was the engine would see severe vibrations around 6600 RPM. The stock damper is tuned for 232 Hz. They devised a revised damper that is tuned for 300 Hz. The revised Harmonic Damper pushes the critical Frequency off to around 8500 RPM.
From this:
To this:
Same plot, zoomed out, more horsepower:
They also did a simulation on a damper tuned for 350 Hz. Perhaps this could be ordered for the right price.
Lastly they did a simulation of a dual mass Damper. They likely recommend against this because it requires rubber to be on the outside and that makes running a pulley a little difficult.
Pinning the damper is highly recommended. I did this using an LS pinning tool that I modified to work on a Vortec 4200.
