I recently built my motor, and it has only 50 miles or less on it. I have beat down motor mounts that need to be replaced with solid or energy suspension mounts. I also use a comp. engineering torque link. The car is gutted so you really feel everything. Now at idle i feel a little vibration. I look in the side view mirrors and the glass shakes slightly. The motor dosn't move around in the bay at all. If i sit in the car and rev it up to about 2500rpm, the vibration dosn't go away. I was under the impression it would smooth out. But it seems to be steady, just at a higher frequency (if that makes sense). I forget if the motor used to do this before the build. My chevy 350 dosn't seem to exibit these same qualities, at idle it's got a bit of a viberation, but smooths out when you give it a little gas. My 306 (motor in question) runs stronger than ever before, and I think I'm being overly parinoid, but just wanted to see what you all thought.