Chevrolet C60s - Front Wheel "shimmy"

[motto (RIP)]

Mention has been made of wheel balancing but what type of balance was done, static or dynamic?
Static balancing has definite limitations in that the location of the 'heavy spot' is not defined axially i.e. it may be toward the inside or outside of the wheel. When weights are added to 'balance ' the wheel they can be just as easily be put on the opposite side of the wheel to the heavy spot and make the dynamic imbalance worse.
Dynamic, on vehicle balancing is a far better option if you can find someone with the equipment to do it as this removes the unknown and also takes the hub and drum into account.

David