Oil pressure gauge - after market
You are better off using an electric as opposed to a fluid type gauge.
I just put a T-fitting where the factory oil pressure sending unit screws into the block. Then attached the factory sending unit to one side of the T and attached the gauge sending unit to the other side. At that point it is just a matter of running your wire up into the cab (wherever you are going to mount your gauge). I used an Autometer Short Sweep analog gauge. You can also opt for the digital, but I like the needle moving (I'm old-school).
Here is a link to some pics that kind of show what I am talking about.
This forum thread explains it pretty well:
Phantom Electric Fuel Pressure Gauge - F150online Forums
Good luck, hope this helps.
Electrical is good.
I learned this lesson when I was 19 years old.

Luckily, the plastic oil line to my dash gauge melted under the hood and sprayed on the ground vs. on to the engine

Luckily (x2) it started while pulling in to work - I noticed the line of oil on the parking lot when I exited my car. It hadn't yet lost ALL the oil either. A new hose and I was in business the next day (with a lot of cable ties to secure the line better). Then drove that car for another 5 years and 90k miles w/o any issues.








