Manual Conversion Vibration

[diesel don]

Hey Everyone:

Upon converting an '82 240D (Manual) to an upgraded 300D-T, we have most of the bugs worked out. She fires instantly and runs out nicely. However, we have one issue that we can't figure out.
At idle and upon take off, there is a rather major vibration. It almost reminds me of one of my other MB's that had a driver's side engine mount missing. The car would vibrate the heck out of you until the rpm's were sufficient to lift the engine off the frame.

1. I did not balance the flywheel because I couldn't find any marks. However, wouldn't this affect vibration at all rpm's? After 1500 rpm's, the car runs out smoothly.

2. I have new motor mounts

3. I had to fabricate/adjust the former crossmember holding the tranny mount. I drilled holes 1" narrower. In the end, this mount might be 1/2 to 1" higher (closer to the bottom of the car) than it was.

Any thoughts?

Thanks, Don