Rockauto flywheel feedback

I'm running one of those flywheels from 440 Source in my 340 Dart and have not had any problems with it. It came with a counter weight bolted to it for external balance engines but just remove it for internal balance application. I see the referenced ad now says internal balance only. I don't have a shattershield so I wanted to at least have a little insurance against a flywheel failure and I thought this steel one would do the trick.