Tom,
I've just finished mounting one of these in my project car (required at the track if battery is re-located to the trunk) NHRA specs require the cut-off to be connected on the positive side of the battery and must disable all electrical systems so you have to tie in the alternator as well. In my case, I ran the main alternator power line to the back (8 gauge wire) and connected it to the battery side of the switch. You can also run the power line of the ignition module to the switch insted to kill the engine.
I used a simple 2-pole switch. If you want to go with the 4-pole with seperate leads for ignition or alternator, Flaming River sells them. (
www.flamingriver.com )
Hope this is of help.
Francis "Turbo II"