I have two 454 BBC cast cranks. I can bring them both to Terry's in a few days, pick out which one you want, and you can have it (free). I also have two or three flexplates laying around so if you're going to need one let me know and I can bring that (free) also. I think that both cranks need to be turned, less than $100 each.
A stock 454 cast crank is good for at least 700 HP. Phuk GM rods, dimples, whatever, they are too many H-Beams out there that are too inexpensive to buy.