Being the contrarian that I am, mine is in the top radiator hose. Most folks don’t like that because you lose the ability to sense temperature if you lose water or your thermostat doesn’t open. It was that way when I got the car so I just left it as it was.
I have my stock gauge working still, so I don’t worry about it.
The interesting thing about having it in the top hose is you can see the thermostat opening and closing.
