Help! Engine Vibration

hi, the dampner is not supposed to wobble, period. did it go on crank easy or you have to pull it on with a bolt? were the two rods, same casting # as the originals? look up the weight of pistons, compare to old weights. all this can be done without tearing into motor. i suspect the balancer is not right. as for internal and external balance, 318's were internal .as far as i know, the 360 and 72-73 340 were external balanced.