I like the 470 B-block option, if it's not going to cost you a lot more to swap to a low-deck setup. You still running Stage VI heads? That would simplify the intake issue, assuming yours are used w/ the RB spacer plates.

However, I, too, understand the thought about why buy a better quality stock-stroke 440 crank... but that's exactly what I did. My whole combination (gearing, converter, etc.) is built around a 440 RB, but I didn't trust the used OEM crank. So, I replaced it w/ an Eagle 4340 3.75" for peace of mind.