How many miles on the upper control arms, both ends?
You don't have a pitman arm problem. Look elsewhere.
When is the last time the tires were balanced, perfectly?
How are they balanced, static or dynamic?
Who set the toe and how was it done?
Can you repeat the shimmy at will?
Do you feel the shimmy try to start in turns about 45-50 and then go away when the road goes back to straight?
What track bar, what track bar bolt?
Have you done the dry steering test with you watching stuff and then repeated it with the motor running? Results if so?
I replaced all the control arms and bushings in the front end with the exception of the axle side upper passenger which didnt want to come out. Bushing showed no signs of separation using a long screw driver to flex it.
Tires are where I thought my problem was, I had discount tire warranty my last set of tires out after having them balanced multiple times at two different shops. One place road force balanced them and assured me they wouldn't leave unless perfect, and discount tire dynamic balanced them I believe? What's the difference between static and dynamic? I now have new tires and wheels and got rid of my wheel spacers with no change.
I set the toe using square aluminum tubing clamped to the rotor and a tape measure.
I can repeat the shimmy over certain pieces or road, speed does change how the wobble feels, but it is not exclusively occurring at 45-50. Cornering does increase the severity of the wobble, but only certain corners. Smooth cornering causes no wobble. Death wobble both times happened on a corner at 65/70 mph
Have had both a metalcloak with 5/8" and 9/16" bolt and Currie with 5/8" and 1/2" bolt with no change. Both torqued to spec often.
I have only done the dry steering test a few times with motor running, I was unaware it should be done while off. First time, i found a minute amount of play in metalcloak heim joint, everything else tight. Replaced with Currie track bar with no change. After having death wobble with the Currie track bar it was done again, to find I could feel a click in the pitman arm tie rod end (turns out this was the dead spot in steering) I also thought the track bar Johnnie joint was moving more than it should. Bolt not moving but joint moving around it slightly. Replaced with metalcloak track bar and new heim joint (had it laying around) with no change.