Hot Rods Wiring Help Needed

I am wiring a '46 ford. 351w, 60's Ford alternator, regulator, rear mounted solenoid, and battery. Instead of running another wire from the I terminal on the solenoid for a full 12
volts while cranking, can't I just run a wire to the starter post. That would send 12 volts
while cranking, it seems that would be the same as a separate wire. Please, no guessing.

 

problem is when the engine starts, you keep providing power to the starter through that wire, from the ignition circuit.

there's a reason they did it the way they did it.

 

That makes sense. Thanks