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
What the professor said. Or, if you don't care about originality and want to get rid of those 1.4 year only parts, get a forged crank and neutral balancer during your engine build. That way you'll be able to find replacement parts much easier in the future.