Relay Wiring for Dummies like me

[67 Burb]

Here's the way I would do it. It is the simplest way to do what you want. Just cut the wire from the ignition switch to the distributor. Add the relay between the two ends like in the diagram and your small hidden switch in the ground wire. When the hidden switch is left closed, all will work as usual and when you want the anti-theft, open the hidden switch. Done.