Locks only keep honest people honest, as my grandaddy used to say.
Whatever method you go with (fuel shutoff, ignition kill) you should place them in the cab.. so if somebody is "camping" your vehicle, they won't see you fiddle under the hood or under the vehicle (a dead give away you're activating some theft deturrent)
Even in a "dead stick" situation, an old vehicle is pretty easy to steal.. with no way to lock the transmission or steering column, it would be easy to push it up on a trailor and be gone.
The most direct method i've ever seen was a guy who welded a ring on his shift lever, and another ring on his seat riser.
He'd put the truck in reverse, then used a heavy gauge steel cable threaded thru both rings then locked with a padlock.
With the steel cable in place, it was impossible to get the truck out of gear.. unless the theif had a way to cut that cable fast.
So I guess they could still start the engine and drive away.. but they'd have to do it in reverse.
I'd say a variation of that method, combined with The Club would be effective.
Sure, they can cut the steering wheel to get around The Club, and they can cut thru the cable to free up the gear selector, but thats alot of work, and can be time consuming.. a would be theif may see both measures, and go for an easier target.
