Some people have used an air/CO2 with a Bimba cylinder to launch the parachute and that could also be connected to the shutoff turning it off at the same time.I will stick with the Ford relay and button to cut power and the main thing is to have it in a good place to de activate the power.

GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/