Old to B Bodies New to A Bodies

We have a couple things in common as I was driving B bodies exclusively and now have a 72 demon..last A body I had was in 66...as in 1966. I've seen the 440's in A bodies and hang witha mopar builder of some 45 years and I'm leaning towards stroking a 400 rather than a 440. It's narrower and lighter and there are kits for 512 cubes. Food for thought.