Those are billet not forged, and they are available now. http://buickracingparts.com/kbr-crankshafts-kits.html
A billet IS forged in a die, but it's not the ultimate strength in a forged Crank you can get, as a non twisted forging has more strength then a billet due to grain flow, that being said a billet will take far more of a work out then a factory block will by some 200%!