Hello CV,
basically most of the new flywheels are 0-balanced i.e. they're good for internally balanced engine. And no, you can't use 0-balanced flywheel from your 383 to stick with externally balanced engine.
If I would be you, since you're anyway going to balance the set, ask the machine shop to make it as internally balanced engine. just carry all the pistons with rings and locks, rods and bearings to the shop and ask them to make it as internally balanced engine. then you can use your 0-balanced flywheel from 383 (make them to check the flywheel for it's preciseness for 0.. also the damper)
Furthermore, a healthy suggestion is to change from cast iron flywheel to steel flywheel.. just to be on a safe side
