I recently replaced the transmission mount on my 66 after I noticed one of the mounting studs was simply gone. I replaced the original rubber mount with a poly mount from NPD. Shortly after the change I started to notice a womp, womp, womp kind of vibration from about 14-1800 rpm that could be felt throughout the car. I noticed the fron u-joint was in poor shape and thought that was the problem. No such luck. I replaced both u-joints only to notice that I get the vibration even in park or neutral. That leads me to believe the problem can only be in 2 places, harmonic balancer or flexplate. Any thoughts/suggestions on other possibilities?

Thanks,

Big Nate