440 Vibration at 2500+ rpm

[Gunner1]

If it's the balance weight missing on the TQ then it would increase with severity as rpm's rise above 2500. By 4000 it should rattle the mirrors pretty good. Exhaust hangers can sometimes cause a surging vibration at medium speeds. If the vibration goes away as you raise rpms past the 2500 onset then its not a balance issue most likely.

 

[6PKRTSE]

I had that same vibration issue on one of my 440 cars. Did the usual. Rebalanced wheels and tires, tried other wheels and tires, changed engine mounts, trans mounts, replaced u joints, tried different driveshaft. Would up being the factory 50 year old damper. Installed a new damper all is well. While the old damper was sitting on my shelf weeks after removal it feel apart into 2 pcs while on the shelf.

 

[Don Frelier]

I had that same vibration issue on one of my 440 cars. Did the usual. Rebalanced wheels and tires, tried other wheels and tires, changed engine mounts, trans mounts, replaced u joints, tried different driveshaft. Would up being the factory 50 year old damper. Installed a new damper all is well. While the old damper was sitting on my shelf weeks after removal it feel apart into 2 pcs while on the shelf.

A 50 year old damper would be my first thing to change.
Part of the reason I worked on my 383 this past summer was I wanted to put a new one on it.

 

[zyzzyx]

If you're going to replace the Damper, replace it with a 440 Source Fluid Damper. Done!

 

[1963JAM]

I think we have a winner for the engine vibration! Dave6T4 with the loose water pump shaft but no leak. Checked all previous posts suggestions and found slight play in water pump shaft. Replaced pump and bad vibe dissipated considerably.
Thanks Dave and all FBBO'rs for the help.