Join Date: Aug 1998
Location: Waldorf Md. USA
If the car ran smoothly when you test drove it, I doubt that the problem you are having now is actually a "vibration" in the out of balance sense of the word. I am betting that the motor is just running roughly due to a carburetion, ignition or other problem. If the flywheel or damper had been wrong, or the motor not balanced correctly, it would have had the problem when you test drove it and when you first started driving it home. You say that it suddenly started doing it, thats why I am leaning towards a rough running condition. Plug wire come off ? Carb float stuck all of a sudden ? Etc Etc Etc. These are the types of things to be looking for.
By the way, when you replaced the damper...is the new one for a 400, with the cutout on the outer ring. This is what the 383 should have on it. The wrong damper will also cause a vibration, but your problem was not there when you first got the car,, so I dont think the damper was, or is the problem.
Hope this helps,
Advanced Automotive Machine
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73