I want to put a direct (mechanical) oil pressure gauge in my car, but am unsure the best way to plug it in. The only port I know to plug it into would be where the oil pressure switch tube plugs into. Only thing is, I know the Fuel pump runs off that plug as well, so if I were to unplug the oil pressure switch, and go with a direct oil pressure gauge, Do I have a issue? whats the best way to do this?
thanks!

You need to tee it in. You should be able to find t-fittings or adapters to do this.

do you know where to find T fittings? also, isn't a T fitting for an electric gauge?

Most auto parts that sell the gauges will also sell installation kits. These should have what you need to hook it up.