You either have an HP 440 with 6 pack rods or a cast crank 440.both are externally balanced and both have different wieght offsets from each other. Buy a regular used or new neutrally balanced flywheel. Take that flexplate and flywheel to the balance shop and have them balance the flywheel to match the flexplate. If you knew what you had, you could drill the flywheel for the correct offset weight using the diagram in the Mopar engine book. Do you have the funny offset balancer on the front?