Dear Barb and mid-60s Buick security seekers,
I did a little more web searching I came across a new immobilizer system from the Swiss that uses your smart-phone as the "key" to unlock your car. The company is called iBlue and here is a link to their product.
http://iblue.eu/immobilizer/It uses Bluetooth to communicate with the phone and has software for iOS and Android. It uses 128-bit encryption like credit cards. This is more important than I first realized because there is a system installed on modern cars that researchers have already hacked!
https://www.engadget.com/2015/08/14/car-immobilizer-easily-hacked/It has a "valet mode" so that when you leave your car at a repair shop you can turn off the system and the car will start without your phone.
It seems to have two downsides. Like my old system from San Diego, I suspect that if your car loses power while at the repair shop, the valet mode will be turned off. In that case, you would have to return to the shop to turn it back on. The other is that it is vulnerable to your phone being lost or stolen. If you can bring another smart-device that has the software, you could start the car because it has a pin code that can be typed in. However, without another device, not only would you have lost your phone, but you couldn't start your car!
They don't explain very clearly how to install the device, but it appears to have the ability to control up to two electrical lines. One way to wire such a thing in an older GM vehicle is to wire the device in between the transmission neutral safety switch and the ignition switch. That's how I did it in San Diego. You'll find information on doing that on page 10-48 and on the wiring diagrams on page 10-108 and 10-109 in the 1965 Service manual. I don't remember how I originally did this, but I think now I would insert a small relay into the purple wire in between the neutral safety switch and the ignition switch instead of completely rerouting it through the immobilizer.
I'm not ready to take on a device like this but once I get my trusty wagon back on road I will be
very tempted!Cheers, Edouard