[motto]

I'm still thinking wheels too Dave. Dynamic balancing would give a definitive answer on that issue.
A simple test would be to drop the rear driveshaft and jack the front wheels one at a time to spin them up using the engine. What happens could be quite a surprise.
Just keep in mind that with one on the ground the one spinning will be rotating at twice the speed showing on the speedo.
Chock the vehicle well if carrying out this test.

David