One thing no one has mentioned is size. For example, a B engine is a much happier fit in an A body than an RB. So a 4.25 stroke 383 would be my choice in a Dart.

About weight: I believe the stock weights between B and RB were heavily (!) influenced by cast iron intake manifold weight.

About compression: just be sure to get the pistons very close to or at zero deck to maximize squish. With the aluminum heads and everythign else in order you should be able to run 10.5:1 on pump premium.

R.

PS: By careful shopping you can take 200 grams out of each piston/pin combo which will make the 440 rev more like a smallblock.

PPS: Unless you already have crank and rods ready to go I'd say go stroker crank and aftermarket rods with 7/16" bolts.