I actually talked to a guy that did this.He said he would do it again.Hes putting out 800hp and never had a problem,He used a 440 stock crank,Higher comp pistons,a few mods for oiling and push rod clearance.Hes been cruising it and occasionally beating on it and said he has had no problems what so ever.He also has a few original hemis and said they are built tuffer but cost much more.He has a girddle on the crank to.He has been into mopar since 1965 and said hes seen it all.He told me not to fear the 440 block,It may not be as stout as the 426 but not a weakling either.