I have a 3 speed on a 74 falcon 500 its a column shift and the shifter armature at the top of the column shattered.
i have replaced it but now the column drops out of the selectors whenever you select neutral and the shifting gears is very harsh its been driving me nuts so any help at all will make you a god in my eyes

It sounds like you may need to adjust the linkages. This is done by putting the box into neutral by actually loosening the linkages at the box and moving the shifters (R-1 and 2-3) both to the central position so the box is defintely in neutral. Now make sure the selectors that come out of the base of the coloum (this is near the steering coupling) are in line, by memory there is a hole in both selectors that you can insert a straight piece of rod of the same diameter that will line them both up. With the selectors lined up and the box in neutral tighten up the linkages at the box then remove the lining up rod at the selectors and hopefully all should work fine otherwise you have installed the coffee pot (The section of the coloum that holds the gear shifter) wrong and have not positioned the shifter correctly into the selector slides.