Anti-Theft Suggestions.

If you have an electric pump, a hidden switch in the relay ground

You can ground your tach lead, and I believe if MSD, there's a trick you can use there, too, or put a hidden switch to break the trigger (small red) wire

If you don't have a tach, run a wire out to the coil neg. and put a hidden ground switch on it.

Some guys use their cigarette lighter as a switch.

If you have a Line Loc/ roll control, you can rig it so if someone figures out how to hot wire the car, the Line Loc is active and locs the brakes at the first stop

Simple things like remove the coil wire.

On my old 63 Chev, you used to be able to put a plastic covered chain/ cable through the hood latch mount, but I haven't figured out how on an A body yet. I'd lift the hood 3-4" and unlock the padlock.

But remember this: Nothing beats a thief with a rollback/ wrecker/ etc

I have not kept up, there ARE cellphone systems you can use, and you've probably heard of "Lojack" but this is a REGIONAL service, and there is NONE around my area for hundreds of miles, so forget that.