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There are 2 styles of factory 360 dampers - ... On the old style, (on the left in the photo from the archives) the weight is added to the outside of the center hub, so the "imbalance" of the outer ring doesn't stress the rubber cushions like the new style.




Very good point, never thought about that. Putting the imbalance outside the rubber might help the damper tune out slight errors in balance but will add stress to the rubber.


Quote:

So I put back in the poly tranny mount to see if it made a difference now that the vibration is mostly solved with the rebuilt damper.



The transmission mount isn't a moving part and therefore can't be a source of vibration. Putting in a stiffer mount will certainly TRANSMIT more vibration from the transmission to the passengers, after all, it was put in there just for the purpose of isolation vibrations.