Alright, so I change some gaskets on my engine today. Put in new head gasket, valve cover gasket, intake manifold gasket and exhaust manifold gasket. Once I have everything put back, I go and start the car and alot of smoke comes out of the exhaust and the engine shakes and sounds horrible. I already double checked all the wiring, spark plug wires and everything. Can some one give me an idea of what could be wrong? my only guess would be that i put the timing belt wrong and that i messed up my timing,