I agree with Sam (which is the reason I didn't add anything above). Knowing what you've said about your car (cruiser, et. al.), the 350/350 would be a good choice. One of these days, I'll replace my motor (which is not matching, and I know the original was lost in a scrape pile in Florida a long time ago). But I'm waiting myself, because the 327/4 barrell I have is a great cruising setup for a powerglide car.
I also noticed on another one of your posts that you are starting to get answers to the issue of transmission and speedometer irregularities. Let me (us) know how that all plays out.