Tail light lens

The backup light switch for your car, if it has one, is mounted on the top side of the steering column under the dash. It would have two wires going to it. If your car doesn't have it, you will see or feel just a hole there. You would also need to get the little metal finger that operates the switch. It clips into the shift tube running down the column. That might be harder to find than the switch. I think the column shift '66 models use the same parts. Oh, the neutral safety switch in mounted in the transmission and has nothing to do with the backup lights on your year, assuming it's stock. Now, if you are using a late '68 and newer transmission, things just got a lot easier. The later torqueflites with the 3 wire neutral safety switch used the other two connections for the backup lights and would easy to wire in. Sorry, you can just swap the switch out. Internals are different too.