Hoping some experts can chime in here... The car is a '70 Charger R/T SE with a 440 Six Pack mated to a 4-speed manual - car has no A/C or Power Steering. I am experiencing a vibration in the engine somewhere, but I can't figure out where. Behavior: This occurs at idle, at speed and with the clutch in or out, so in my mind it seems to be either the harmonic balancer or the flywheel. The engine seems 100% healthy and this does not seem to be a cylinder contribution issue as I can feel all over the engine at idle and I don't feel/hear/see this vibration if that makes sense. Also, and I will try my best to describe this verbally, but the vibration feels rotational to me. If you are sitting in the drivers seat you feel almost like you're experiencing the effect of leaning against a washing machine that's out of balance - which leads me to believe it is indeed in the rotating assembly vs. a cylinder contribution scenario. Thanks! Any input is appreciated!