[chiphead]

That diagram is missing the wire between the keyswitch start position and the starter solenoid.

How about wiring it to an idiot light? That way if the oil switch fails or you lose oil pressure, it doesn't kill the car on a railroad track or in an intersection?

If you want it to kill the ignition, you'll need to wire it between the key run power and the ignition coil. A separate bypass wire would be needed for starting because there is no oil pressure at start. Pretty much exactly how pontiac wired their ignition systems to bypass the points resistor wire during crank.

It may cause some annoying fail to starts if there is no oil pressure when it fires and you let go of the ignition. Which is why the switches are sold for control of a fuel pump or a warning light.

I had one of those exact switches on my other 67 when I had a Comp 140 fuel pump and nitrous. If the engine stalled, it cut the fuel pump so it wouldn't risk drowning the Q-jet. I had a manual override switch on the dash so I could bypass the pressure switch, if I wanted to run the pump with engine OFF or I was spraying. Don't want the ole piston-melter 5000 if the fuel goes away but the nitrous doesn't.