Originally Posted by TimS
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.


When did the vibration start?

Always there since the engine was built or did it start on it’s own or ?

If from day one realize that a normal 400 is externally balanced - meaning it takes a special damper and converter or flywheel.