Understanding External Balance

Helping my brother with his 360 we are going to be sending to the machine shop. I had my 360 all internal balanced when we stroked it to a 408 and have never messed with external balance.

Please correct me on any misconceptions I have. My understanding is that the 360 harmonic balancer is not externally balanced to that exact engine but a standard amount of weight is added to all 360 cranks to keep them within a certain balance tolerance? Also you need to either have an external balanced flexplate or Converter. The flexplate preferably external balanced so you can use any converter. When we bring everything to the machine shop we need to make sure they have the external balanced balancer that was on the engine or another 360 balancer and the external balanced flexplate we are going to use. This way they can be sure everything is in balance when they put the new KB flat top pistons on and add or remove weight from the balancer and flexplate to make sure it's right.


Thanks a lot