I'm getting a little confused with engine balancing for a SBC. I'm looking for a new SBC motor for my 69 Camaro and I am considering either a 350 or 383 stroker. I realize that SBCs with a one piece rear main seal (ZZ4) and most strokers are externally balanced. I've read and heard that for an externally balanced motor, the entire rotating assembly (crank, rods, pistons, and harmonic dampner, flywheel/flexplate) must be balanced as a unit. So that technically, if the dampner and/or flywheel is changed on an externally balanced motor, the correct procedure would be to rebalance the entire assembly. If this is true, how would this work for some of the externally balanced short blocks (without dampner/flywheel) that many of the builders are selling? The tech lines tell me that all I would need is a flywheel/flexplate for an externally balanced motor and just bolt it on. Shouldn't it be balanced with the crank, etc? Thanks.