I've got my 63 falcon home and the car won't start unless its in drive thats when the shifter needle is in the neutral position. It had a 2spd from the factory and a 3spd now. Is this a linkage issue or a switch malfunction somewhere?
I would think it's a linkage issue. Sounds to me like they left the fordomatic linkage in. Sounds like it's adjusted so that when it says it's in park it's really in reverse. You might be able to adjust it out so it goes into park properly, but you'd lose your ability to go first.
My guess is the best fix would be to find a column shift out of a newer falcon or mustang that came with the C4, or just scrap the column shift and get an aftermarket floor shifter.
Of course, I'm no expert in this area. Someone else will likely know more.
Might also be a neutral safety switch issue. If you have backup lights, do they come on when the shifter is in reverse? If not, put the shifter in reverse, loosen the NSS and slide it around till the lights come on. Then tighten it down.