Jeremy,
I don't think that's a stupid question. Think of the diode as a one way valve for electricity.
Your rig has a HEI...will this work? I don't really know for sure, but I don't know why not. It's a common terminal switched on with the key, the same as a conventional ignition.
You can buy little pigtails with a diode already encased that plug between the DA terminal and #1 brown wire. This would only be needed when you tap into an ignition source. It prevents run-on when you turn the key OFF.
Stuart
