[al lkosmal]

This does not necessarily line up with your over-rev incident, but check the fan pulley/fan interface. My pulley wore into the mating surface (belt too tight), to the point of causing it to go off-center and create an imbalance that could be easily felt as an engine vibration. It drove me nuts, I checked everything three times, ran great...except for that vibration. One day I noticed the fan belt was vibrating......I mention it, because it is very easy to check......and you never know, you could get lucky and it's that easy.

Regards,

Al