Disconnect switch wiring

Is there a way to do it that doesn't involve running a massive, constantly hot wire through the whole car?

Yes there is... It takes some extra wire and a solenoid or two depending on what you want in the end. The two main lines to be cold, starter line and alt charge wire.



This method take all the load of your starter off of the master cutoff. I think I have about $30 for the ford starter relay and a CD relay for the alt line.

There are other ways to do this, using just a ford relay, but, that still keeps the alt line hot. Upper CD solenoid, left side goes to Altenator, right side jumps to starter solenoid in/battery hot. Left side of starter relay goes direct to starter.

Here is the last one I did for my Swinger 340.