To the OP....The problem would have been the top section of the balancer.....The top and centre sections are held together with a rubber (per say).....It is a common problem for the 2 pieces to "seperate", causing the wobble you describe, especially with age....It also allows the timing mark on the balancer to move from it's original position, when the balancer was made, which can be fun, when re-checking the timing.
Providing you're just using the motor for general driving duties, just walk into any autoparts store and buy a new one....The bolts you currently have should go straight in...