Here is a picture, re-enacted on the work bench of the Ford shifter and one rear bolt.

  Use a pair of Channel-Locks as a lever by leaving the two rear bolts in place but loose so the bolt heads can be used as a fulcrum.  Then invert the channel-locks and hook the serrated edge under the flange on the stock shifter and rest the plier against the bolt and pop the old shifter loose.  Remove the two rear bolts, remove stock shifter  You won't have to get under the car when installing an aftermarket shifter if you use this method.  .