Ol' green had a wicked shimmy that began at about 55mph. I jacked it up and wiggled and tugged at every part of the front end and determined that it was time to replace the kingpins. Got my pins and bushings from Chev's of the 40's and went to work on it last Sat. The passenger side was easy, just a few whacks and it fell out, but the driver's side was a whole different story. I finally took it to a machine shop and had it pressed out. Got it all back together today and took 'er out for a test drive. Wow! What a difference. Smooth as silk.
So just a word of encouragement here: it's not as bad a job as it sounds. Worse case, just take the axle to a machine shop and for a few $$ they'll remove those stubborn critters for you. The results are definitely worth the trouble.
