The OEM style damper on my 383 is worrying me alittle. The rubber is coming out some and has cracks. I want to go with a Streetdampr for externally balanced SBCs. Will I need to take both the new and old dampers to a machine shop and have the new one matched in balance with the old one so I won't throw off the reciprocating assembly's balance? I don't even know if the dampers are modified in the balancing procedure or not. I just don't want to change dampers and have it be inbalanced and ruin my engine.

Thanks

 

The balancers don't get balanced with the rotating assembly. The flywheel does (externally anyway). Of course there will be a slight difference between the balancers but not anything requiring a rebalance of the engine I'm sure. I'd run it and not worry about it.