Help! Engine Vibration

I have the same problem. I had my 360 rebuilt professionally. I have a slight woble on my balancer though. I had the 904 rebuilt that originally came with the motor. I put the same parts I took off the trans and put back on, with the exception of a new, factory torque converter. The only thing I could think of is when we had the motor on the cherry picker, (before the motor and trans was rebuilt) the weight of both the engine and trans was to much for the picker and the motor fell to the ground. Unfortunatley, the balancer took the brunt of the impact. I have since bought a balancer. It is a Pro-street by cyco systems, which I bought from Mancini. It is externally balanced, and will put on the motor this spring. I'm wondering what the issue could be as well.