I just put a viper alarm in my 78 620 flat bed and power locks in both doors its really not that hard and gives me piece of mind but i have over $1500 in stereo in my little girl. If you want to do a dead man switch put it behind your ash tray so it has to be pushed in to start and when you get out put a pen or something in the way so it wont close and then wont start. Just a few ideas for you i work at a stereo shop so we do some cool hidden switches from time to time if you have any questions just let me know, and datsuns are so simple to put alarms in if you need color codes just hit me up.