I don't see a reason to tuck the #s motor/trans away, unless you know you're gonna do something silly and hurt it bad. If you want a 440, go for it. It doesn't make sense to me to tuck away a B and put an RB in its place. Once it is up and running, there is enough difference in parts and fitment that I doubt the 383 would ever find its way back in. If you like the 383, build it and run it.
Travis..