650-700hp from a carbureted 440? You might want to start with the block/crank issue at that horsepower level. Better to be safe than - - (SORRY!!). Otherwise, BIG CFM CARB(S)/good intake, large-ported heads/compression, the RIGHT cam/valvetrain setup, good exhaust setup and good tuning skills will get you there. Chances of a near stock parts 440 setup making that level of power (save for a well-built TURBO combo) is nil!