340/416 vs 383 vs 440

Not trying to be argumentative. It seem like you pretty much want a 416, and was just flirting with the idea of big block. Which I say go for.

But don't decide small block over basically a set of motor mounts :) If your building a 416 to 500 + hp your gonna need a rad anyways, you just stated you need tti so big or small block no matter there. Should step up to a scattersheild bellhousing anyways but if not how much is a 440 stock bellhousing anyways. So that leaves mounts. And you do have two decent small block intakes to work with but again you could sale it all to someone who wants a 13.40 340 car for a decent amount $$$$ and build a 440 or stroker 440 with a trick flow top end etc..