Its going to be over priced Im sure. The 380hp 360 magnums are now around $5000. Im sure they will want around $7500 for the 440 and 550hp isnt much for such a big cube small block.
The 360/390 HP (no more 380) is $4400 from Mancini and there are places that are cheaper. You are right about the 440 being big bucks but then again all the big inch small blocks are serious cash.