I usually drive local. And the other day had to go on the highway. I have a 85 300sd just for reference.
Everytime I went slightly over 60mph, I feel a slight shake.shimmy in the front end. Needless to say, I stayed under 60 the whole time, which was aggrivating, cause the speed limit was 65.

I have brand new tires, just spun balanced, and checked all the front end parts, everything is fine. Any ideas?....I am lost.....