360 flywheels

So what is it about external balance flywheels for 360s that makes them so expensive??

I looked up a flywheel for a 360 and all I found were ones that people are mega proud of, like 3 times a regular neutral balance flywheel.

What gives

Compared to neutral balance flywheels they either have added weight like this 360 / 727 torq converter, or are drilled in areas to offset the needed weight to balance the external balance crankshaft.

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