chevy 350 with a vibration issue

Hi there, I have a 69 chevelle small block 350, 4 spd sag trans, total rebuild on motor, when I built the motor it sat completed for 2 years before I installed it, I bought a standard harmonic damper from advanced auto, and now with the car at idle I can see the damper does not run true, and I have alot of vibration at idle, when I take it on the freeway my hurst shifter really shakes and vibrates, could the damper create that much vibration? I have not checked the drive shaft for balance yet because it vibrates at idle. What size damper should be on a small block 6" 7" 8"

When you built the motor did you have the rotating assy. balanced?
Yes, a damaged damper can cause the engine to vibrate.
I run a 6" damper on my 383 with no vibration issues, an my engine is completely an aftermarket build form oil pan to air cleaner.

Keith

My question is how did you install the damper??.:confused:

I had the crank turned professionally, as far as the install of the damper, I honestly can't remember, but I have been reading and it should be pressed on not beaten with a block of wood, it could be time for a new one but the size has me wondering which one will work.

You could have damaged the thrust bearing? But if your damper is not "running true" it could be damaged and will viberate I would make some calls and find out which one belongs on it.