There are a number of ways to accomplish:
- The HEI kill switch method described above I can't comment on, since the website given shows no picture or schematic of how the switch would operate, but I'm guessing that the switch will just open up the +12v going to the HEI when activated, which would prevent the car from starting.
- If you have an electric fuel pump and can find the fuel pump relay, you could easily put a switch in the ground wire of the relay so when the switch is open, the relay will not operate, no fuel will pump, and the car will not start.
- I'm using a more complicated method on my Pro Street Nova, by wiring in a latching relay that completely disconnects the battery from the car. It has a provision to keep the computer, clock, etc., alive when in disconnect mode. It also provides me with battery run-down protection when the car is not being used, as it will not be my daily driver. Way more complicated to install, also, as you will have to fabricate battery cables, etc.
Good luck