68 Dart GTE Project

Well since turbos are easier on the rotating assembly I would bet that a 340 with the factory steel crank, maybe the TA rods and low comp stock pistons might be able to handle it or at least be able to handle near it.
Maybe, and maybe a Magnum will take it, but probably not for long. It's still a discussion of an engine that was designed for forced induction vs one that isn't.