I have had a nasty vibration in my car since I got it running. I put about 200 miles on it 2 years ago, the tranny mount was shot so I put a new one in hoping the issue would go away, and it got 20 times worse. I haven't really driven it more than in and out of the garage when I want to work on a DD since. The car came from a guy who built it in 83, and parked it a few years later. I have no idea why it was parked he said his kids were born and that was that, maybe it had other issues so wasn't driven any longer? Beats me, it came with a Mallory dual point set up, but the dist. was gutted. I never heard it run before buying it 7 years ago.

The motor is smooth as can be at idle, it doesn't shake at all with your hand on the valve covers. Around 1500 - 1800RPM it starts to shake on the inside and its not comfortable to even sit in, it rattles your teeth. Here's the front of the flex-plate, and it appears the left ears on the stock plate (looking at from the front of the car) are bent. What does a flex plate failure look like? I have heard they crack, would that cause this issue? Obviously the plate is damaged but could it be the tranny/converter?

The motor is a 9-9-68 casting 340 with the early (thinner) dampener which I already swapped with another one I had, the converter doesn't have any weights welded onto the flat spots. I thought this was all correct maybe I'm wrong? It's a 727, and it vibrates in park, neutral, and all forward/reverse gears. Timing is set at 28 or 30 flat with no vacuum advance, electronic conversion Evan's harness and MP dist, orange box.

Thanks in advance, TC...