74 Dart Vibration

I'm not sure what to do in your situation.

When I had the machine work done on my 360 I gave them the crank, harmonic balancer, and the cutout fly wheel for balancing. I had them balance that entire rotating assembly. That way it's compatible with any neutrally balanced converter.

My best guess is talk to the place that built your 360 again and ask what exact parts are they saying you need.