Is this a vehicle you had been driving and the problem just started or is it a new project that you know nothing about ? It could be as simple as the nuts on the shift rod adjustment loosening up and the shift rod sliding in the adjustment.On a 64 its proberly had shifter parts worn out and replaced more than once so at this point we dont know what condition yours is in. 1st Find neutral in the transmission. 2nd, look under the hood where the shift linkage is on the steering column. there are 2 levers there attached to 2 shift rods that go down to the transmission. those 2 leavers are suppose to be aligned wtih one another. Its been a while( many years) but I think there should be a line up slot on those levers that you can use a nail or a drill bit to help you line things up.3rd Once you loosen the adjustment nuts it helps to have someone in the vehicle to hold the shifter where you think neutral should be.4th Make sure any metal or rubber grommets are replaced that may be missing or worn.5th once the adjustments are made and everything is tightened up, see if it works. If it does You can have the person in the vehicle shift the linkage enought times for you to observe what is going on and at that point You may be able to make slight adjustments to improve it and make the operation smoother. 6 MAKE DARN SURE THE PERSON IN THE CAR KNOWS WHAT THEY ARE DOING SO YOU DONT GET HURT OR RUN OVER.