Starter solenoid

[Eman]

Originally Posted by FireSale

Another trick: If you use a Ford style solenoid fender mounted to send power to the starter, there is a reverse voltage surge that travels on the small wire back to the starter button when the switch is released. This is caused by the collapse of the magnetic field in the solenoid and can damage the starter switch or wire to it. I replaced a push button with thin gauge wire with a beefy momentary toggle switch and 14 G wire because of this. You can also wire a diode in that small wire to block reverse current if you understand those things.

This is a good point, I've had it happen but not with every GM starter when you use a Ford solenoid.
Another thing you can do is use a Ford style solenoid and use it as a relay to trigger the 12ga wire to the GM solenoid on the starter. You should use a relay on a GM starter switch circuit if you use a micro switch for a neutral safety switch.