383 440 swap. Same flywheel?

Don`t know if this might help. I have an externally balanced 440 cast crank w/ Torqueflite in my Duster, has what I think is an aftermarket front balancer and the factory low stall balanced converter - soon to be replaced. I have the weld-on weights to balance the rear for a new unbalanced converter but I believe B&M makes a flexplate for cast cranks only (#10237) which may be a better solution for the rear, B&M could tell you if it would work for manual trans as well....Anyone else familiar with this issue?