I don't know about the dampener yet. The Pontiac one has the pulley grooves on it, and I "think" it is different than the chevy ones. The rubber on mine is definately comprimised, so I need to get mine rebuilt at a minimum. Not much out there in the aftermarket for these. What ever I use I'll get before I send the assembling for balancing.
Here are two non-ideal pictures of mine when I test fitted it on the 292 crank snout. The belt cog is not part of the dampener.
