340 engine (flywheel)

just need little guidence here,,,,so Im looking to replace the flywheel on 1972 340 Duster,,,Im finding I need to know if flywheel should be applicable for balanced or unbalanced engine,,,not sure about this,,,I do plan on having engine balanced and line boared
Thanks
And technically, it's not a matter of "balanced" or "unbalanced"- they're all "balanced", just balanced differently; internally or externally.
As HemiSSDart said, you need to look at your harmonic balancer, if it's a cast crank with this balancer, it's externally balanced:
1694270260767.png

1694270294533.png
If it's a forged crank, it is internally balanced and uses this balancer:
1694270418924.png
If it's externally balanced, you need the specific 340 cast crank flywheel, but not the externally balanced LA 360 or Magnum 5.9 flywheel, which are all different.
If internally balanced, any of the internally balanced flywheels will work.