Balanced Crankshaft (Need Help !!!)

it is possible that the person before you put the wrong crank in. did you drive with this motor? cast cranks also have flash marks from the molds. yes late 72 auto 340's and all 73 340's(i believe including manual cars) should have cast cranks. if you have a forged(neutral or internal) crank, great. just get the parts accordingly. is he balancing the rotating assembly? crank, rods, pistons, rings, bearings,etc.? i sure hope so. even new pistons can throw it off a bit. i believe the factory had a 6 gram margin of error.