Hello everyone, I just finished a rebuild on the engine and transmission. Had all of the engine internals weighed and balanced. And the transmission rebuilt. The car has a shake at idle and at low rpms and when giving it initial gas to get her moving. After its going it runs fine no shaking at all. Until we stop and it is idling. The motor mounts are new and shouldn't be broken so I am looking into other causes for the shakes. Any insight is greatly appreciated.

I'd rule out something as simple as an ignition miss before suspecting bigger things.
Look at all your plugs; you might see evidence of one or more misfiring.

Likely something simple; ignition as detailed above, a valve adjusted too tight, something like that.