Likely 383 swap-parts advice requested
All sounds good so far but I'd put an overdrive tranny in it for the distance/street driving needs you're talking about. This link will set you up for putting in a 200r4 in there.
[ame]http://www.wilcap.com/426350.PDF[/ame]
http://www.wilcap.com/downloads.html
That's assuming you don't mind using a GM tranny in a Mopar.