Don,

Tried posting this yesterday but the network/website was flaky.

Mike, I like the diagram. I may need to think about this a bit longer, but I think with the cutoff on common between chassis and battery, the car will still run on as the alternator is referenced to the chassis and will continue to generate power to ignition and accessories (fuel pump, coil etc albeit "dirty" power).

In your diagram, I would put the cutoff between the starter and the ignition switch. Although, like I said before, there would be many ways to accomplish the same thing.

I'm pretty sure at this point cutting the battery ground will not stop a running motor if the alternator is still pumping up the positive supply.

I'll concede I know very little about mechanics and cars in general and am very new to hot rodding but I do know a thing or two about electricity as this is my profession.

Another two cents (am I up to a dime yet? )

Chris