You can also use the shifter from a 75 240, though it has the switch for the overdrive on top of the knob instead of on the steering column. You may in fact prefer this. (assuming you are going to install an M41)

In any case, you will want to get the complete assembly, transmission top cover/shifter mechanism, all together, from one car, as there were several different types over the years, and while you can use any of them as a unit, on any M40 or M41, their component parts are not always compatible with each other.