Have been working on various vibration issues with my 72 Roadrunner, 400, 727 car. I have one with the motor from around 1000 to 1200 rpm or so while the car sits. So pronounced that the steering wheel and dash vibrate quite a bit. Doesn’t do this at idle around 800 rpm or when you get in the 1300/1400 range. I unhooked the alternator, fan and power steering belts. Still have it. I noticed the crank pulley is pretty wobbly. Bad crank pulley cause this issue or does it sound more like a bad damper?

Thanks.