jporter.s281gt

I raced from a dig and when shifting from 3rd to 4th accidentally went into 2nd and immediately after my car had no power while driving and began to knock and shake as if i had a wheel out of balance and while in neutral has a very loud rattle but if you press the clutch the rattle stops and you can still put the car into gear and go i fear i've either dropped a valve or worse please help!!

VTX1800N1

Well, the rattle stopping when you press the clutch would indicate a clutch problem. If it were me, I'd be pulling the plugs to run compression and leak down tests to be sure of the condition of the engine.