Anyone ever had an engine balanced twice? I had my 383 balanced for a flexplate so I could run an auto behind it. After I rebuilt my auto the idea of going back to a 4 speed has been heavily entering my mind. Now at this moment I don't forsee even installing the 383 in my S10, instead I would like to put it in my Dad's 1969 Firebird that presently doesn't run. But that has an M21 4 speed, so it too would need a flywheel. So ever have an engine RE-balanced? I would think that since the flywheel will be added weight it would be doable. Anyone? The big thing is, this is an external balanced rotating assembly.