[Kenth]

FB66,
I actually "cheated" a bit by using a Ford solenoid. I routed the battery cable from the solenoid from the front under the engine mount and shorted the S terminal to the battery terminal on the starter solenoid connections with a copper strip. This way there is power in the battery cable to the starter only during "start". I connected the S cable and the car's positive cable to the rest of the electrical system to the hot terminal from the battery on the Ford solenoid.