383 cast or forged crank

To balance the external balanced motor they would need the torque converter. They can't spin your torque converter on your crank on the balancer (the stator will move around on them and give them a bum reading). These guys must think Mopars are like GM engines and have the weight on the flexplate. You could use an aftermarket weighted flexplate for balancing then you would use a neutral balance converter in your car.

Someone might have put a 400 crank in that motor also, they have the same stroke.