Hi there, I am new here but have some input to your problem. I am an auto technician by trade and the worst thing is when a new problem arises after a repair.... but this is always somewhat easy to diagnose. Did you remove anything else on the car during the job? Something like a vacuum hose, ignition component, etc? Aside from that, if you did warp the pulley it'd probably be visible from the side. To narrow it down, remove the belt and start the car (this will be fine for a few seconds) and see if it still shakes. Then you'll know if it's belt or pulley related. Don't let it run long like this though, no water pump or alternator. If you post your results I'll get back to you on other ideas.