If theft prevention is your goal here's what I did:
I use an
Autolock . Harder to cut through the brake pedal than the steering wheel. I also have a fuse on the battery wire to the ignition, under the hood. It's a blown fuse when it's parked. If (when) they get through the Autolock, hopefully, they'll waste a lot of time farting around looking for a kill switch that's not there before giving up or going under the hood- which you can rig up to lock if you like. Certainly not fool proof but a good effort.
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69 C-10 LWB, 350, 700r4, 3.73 posi-traction, front disc brakes. Built for the desert-
She can take the heat! Vivat Rex Chevus!