Baradium
Is correct
Flex plate = auto tranny
Fly Wheel = manual tranny
The problem is you need to find out which crankshaft you have.
If it is a turned down 400 crank you will need the damper and flywheel or flex plate for a 400 (externally balanced)
If it is a manufactured stroker crank that has been internally balanced you can use the damper and flywheel or flex plate from your 350 (internally balanced)
__________________
|