1974, L-82 convert

I would like some feedback on security devices for a '74 convert L-82.
 
Years ago I setup a switch between the condensor and coil of my Datsun 280Z that worked well. The L-82 has been converted to electronic ignition, so this is not possible, but is there a wire or circuit that would lend itself to this ?
 
Any other ideas on convertible security ?
 
BC

With a GM HEI distributor you can dissable the ignition by breaking the main battery power going into the ignition system or by breaking the the trigger wire comming back from the pickup coil to the ignition coil. If your running an aftermarket ignition I would think there would be a similar circuit you can break with a switch.

I've done simular, only went under dash and put a switch where the wire goes from  the bat to the ignition switch.