For a typical bracket car it really doesn't matter which way you go. I'd be more worried about things like header clearance than the power difference. The RB has more intake manifold options and better main bearing selection. You can also put a longer rod into the RB and the crankshaft is a little stronger.

If I was building Mopar crate motors I'd just go with a nice simple +030 440 block with a 4.250 stroke and call it good. Very simple combination that should work great for most bracket cars.