Engine/drivetrain vibration?

Locomotion:

Thanks for all your help. Sounds like you know your stuff. I've owned this car almost its entire life, so I'm pretty darn sure it has the original cast crank and balancer. However, I will follow your advice and double check these parts just to be sure. My current repair guy seems more and more convinced that the problem goes back to the machine shop that handled the rebuild. In his view, the vibration exists when the TC has the weights -- and it's still with the weights taken off -- so that eliminates TC as the culprit. He's already ruled out engine mounts, tranny mounts, and exhaust system mounting. So now he's wondering if the machine shop resurfaced the original crankshaft during the rebuild and somehow threw everything out of balance. Is that even possible?

The invoice from the machine shop indicates they did balance the engine as part of the work. How could they have returned the engine out of balance?

FYI: This was a pretty standard rebuild; the machine shop installed the obvious new parts but maintained the factory specs (with the exception of a slightly hotter Comp cam).

The owner of the machine shop came over today, listened to the engine, and confirmed it's got a pretty significant vibration in the area of 2,500-3,500 RPMs. He going back to the original guy who installed the engine for us after the rebuild (different shop than the one now questioning the vibration) to see if they have any answers.

I can see where this is going...my current repair guy will say he's checked everything and can't find the problem. That means the only option will be to pull the engine out of my freshly repainted and correctly restored engine bay :sad8: and send it back to the machine shop for some kind of re-do. That should set me back another 2 or 3 grand. But what happens if the engine goes back in the car, after all that hassle and expense, and still vibrates??

What a pain in the *** this is turning into!