5.9 Magnum to replace Older 360, flexplate?

I have a 64 Fury with a later 70's very tired 360 in it. It has a pretty much stock newly rebuilt 727. Attached to it. I want to install a 2000 magnum 5.9 converted to carb in place of it. What do I need to do for a flex plate? Can I use my older flexplate and Torque converter? Is there a conversion flexplate? Thanks