[Jim Sims]

(1)Check your ignition points dwell (gap) first; then look for a loose wire to fix the tach.
(2) Speedo appears to be a badly worn drive cable (real pain to replace - runs through tunnel to front of transmission) but given the vibration level you relate you may also now have some worn bushings in the speedometer head. I do believe you could have just pulled the speedometer head backwards out of the dash (it's retained by a rubber grommet) and undone the drive cable connection nut when the vibration became excessive. Also never reset the trip odometer while the car is moving; such action can strip the plastic drive gear inside or break it's hub's bond the the shaft it is mounted on. Cheers, Jim