cgresham1212,

A rotating component is usually the cause of a shimmy. With all the work you have done to the front end, I would suspect a tire or tire assembly for sure. Loose tie rod ends or a sloppy steering box will exacerbate the problem, but it usually starts with a wheel or tire.

If the problem came with all the upgrades, my only thought would be how well the new tapered roller bearing setups are seated on the shoulder of the spindle.

Stuart