Sounds like you are talking about something like an oil pressure safety switch, Holley P/N 12-810?

Not a bad idea at all. I have total manual control of my pump via the toggle switch. I like to be able to run the pump without the engine turning over. It's good for filling the bowls if needed or for when I run her dry of gasoline.

I've got OCD when it comes to scanning gauges so I figure I can shut her down quick enough if I lose the oil pressure.

Kitz