Another New Guy with questions.

Hey Mike -
First off, welcome to FABO!
Have you considered using a 200-4R trans? They'll fit in an unmodified A-Body tunnel and offer a 0.67 od with a better gear spread than a 727. I'm using one in my '69 Dart build. Non-computer too.
Several really good threads about this trans on FABO.
Check it out.