Will I break this crank?

Great advice below!
You’ll be fine IMO.
Plymouth 65 said
Get a good crankshaft damper something like an ATI Super Damper or Fluid Damper. These will reduce the torsional amplitude of the crankshaft. 65'
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408 swinger said
Make sure it's balanced properly. I ran a cast crank 408. Trapped 7200 regularly.
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