Engine/drivetrain vibration?

"If it was internally balanced like an early 340 then a neutral balance 340 vibration damper would fix the problem. No weights are on the converter now so nothing would need to be done there. This is all assuming it was internally balanced like an early 340 which I am not sure they did?"

This sounds like a logical solution, however, wouldn't you still need to perform some kind if balancing on the drivetrain -- even if you now have a neutrally balanced engine, torque converter and harmonic balancer? This approach might improve the vibration, but I still don't see how the drivetrain would be fully in balance. Making I'm making this too difficult.

Thanks