I'm done with this. You want to argue that you can use a Dodge Cummins flywheele, pleas go on with your bad self. I hope it works. I have my doubts, but , whatever. Until You have actually done the swap, as I said, it is totally irresponsible to recommend it as an easy solution to those who ask. Sounds like you want to use Snuffy as a guinea pig on your little experiment.
How can you say that the ring gear on the F600 with a Cummins 8.3 is the same thing as the Dodge 3/4 ton Flywheel. when You posted a link to a swap which totally disproves it.
As for posting up information of what will probably work, The link you posted would most likely work fine, depending on the input shaft length of the 5063.
Maybe someone could measure one and let us know.
The only point I'm trying to make, is that it isn't going to happen with a Dodge flywheel. Those pictures speak for themselves. I really don't know why you would want to use a 13", when there is perfectly good 14" for essentially the same price.