Nice build. the injection pump has a vacuum operated fuel shut off, it can be a real pain to remove/install but when it's working you just have to apply vacuum, can be done with a line to the cab that you just plug for the switch. I saw an astro van swap, where the guy used his thumb to on the vacuum line to kill the motor. edit: on this high compression motor you do want a battery of about 1000 CC amps especially in a freezing cold environment.
I have the factory vacuum pump so I ran the vacuum to the Alda over boost solenoid and then the other line to the fuel shut off, power wire ran to ignition so when ignition switch is on it holds vacuum back and when key is off it allows the vacuum to shut it off.