I have owned this car (69Z28 with a 302) for 36 years and the engine has had a small vibration in it ever since. I noticed the vibration when I first bought it in 1978 but I did some street racing with it anyway. I have recently finished a complete restoration and now I'm focusing in on the vibration. With the car not moving, I can feel the vibration when I race the engine to maybe 3000 rpm with the clutch engaged or in neutral and the clutch disengaged. I'm a steel fabricator by trade and not a mechanic. Could the problem be the flywheel or the harmonic balancer. Please advise.