[Eman]

OK, I understand about if the battery is in stock location you don't need a cutoff at the back of the car.
You mentioned cutting alt. power at WOT with a 1 wire alt. Doesn't matter where the battery is cutting power to a running 1 wire alt. is not recommended and can hurt the regulator.
If the load of an alt. is enough to warrant cutting it off the easiest way is with an alt. wired like the factory did it. On a GM style all you need is the heavy wire like a 1 wire and a wire powered by ignition feed with an idiot light in the circuit or a diode to prevent feedback which would keep the ign powered.
Generally the only reason an alt has much of a load is if the battery is low or you're running a lot of accessories. My car is a bracket car and I charge between rounds while cooling mostly to eliminate the draw on the battery. This way the alt. only has to replenish what is drawn from starting the car and what the ign and possibly the taillight draws.