Front wheel shakes

Just bought a 97 a couple of weeks ago, replaced both front wheel bearings. I am sure a motor, or tranny mount is bad would that cause the shaes at 30+mph?? Any ideas appreciated! Thanks..

are your tires balanced? also make sure your tie rod bushings are ok here is the picture.
http://www.thepartsbin.com/images/products/images/moog/K6531.jpg

location: under the hood in the middle of the firewall

You didnt swap the two front tires around did you ?
Could have a busted belt causing the shaking.