This is the electrical portion of the new for 1970, locking column mounted switch. Works for both tilt and fixed columns. This rod actuated device is mounted on the top of your column under the plastic collar cover. See page 33-02-06 of your 1970 shop manual for proper installation and adjustment. Working, used ignition switch. This is only the electrical side, the mechanical key and lock section is not included. These are tested and repaired as necessary by our Electrical Dept.
Ford part number D0AZ-11572-A.
While there's currently no reproduction of the 1970 ignition switch, you can adapt a 1971 switch to work. The 1971 switch is widely available. This post on the Classic Cougar Community Forum shows how to modify the new '71 switch work in a '70.
Here is a great tip found on www.mercurycougar.net The plastic and metal portions of the switch are held together with crimped connections that can work loose over time. Once they're loose it's possible for the metal contacts inside the switch (some of which are spring loaded) to lose contact with each other. It's also possible for the contacts to work out of alignment over time. If the plastic part is loose you can try using a wire tie told hold the assembly together. Is the switch works properly when secured that way you can either keep the wire tie or secure the crimps with some glue and you'll be good to go. If that doesn't work you have two choices: 1. Replace the switch with either a new (expensive) or used (risky) switch. 2. Repair the switch. If you can disassemble it without breaking the plastic it's possible to clean and realign the internal contacts. Once that's done you can glue or wire-tie the assembly to hold it tight. This is tricky, though because you have to deal with multiple spring-loaded contacts and you need to know which connections are supposed to be "hot" in each switch position. I've got two used switches that I've disassembled, repaired, and tested to confirm working condition, so it's definitely possible. I also broke the plastic part of another one so I can also confirm that it's possible to make one really ready for the trash can!