Pulsating vibration while cruising??

I know that my converter is missing the external balance weight, but didn't think it would matter this much. Do you know where i can get these weights and where to mount them on the converter?
Should be interesting to see if you can attach a weight to the TC with it installed in the car?
Have you checked the drive line angles?
If the angle(s) are off it can cause u joints to vibrate and fail.