Thing is we have no way of knowing how much shake/vibration you're talking about. A lumpy cam has a noticeable rumble that it will transmit to the chassis through poly mounts. But that's radically different than an engine miss.
What is your engine combination? If the engine is pretty much stock, I wouldn't think there would be a whole lot of "thump" to transmit. Stock engines tend to have low duration, low overlap cams that run smoother than hot rodded engines. If it's hot rodded, then I would expect some mild shaking. All depends. When you say shaking, are you talking about a slight left-right, left-right movement that you an barely feel in the driver's seat? Or are you talking about you can't hold a cup of coffee because it shakes it out of your hand?
