They make two different versions:
Oil pressure switch (for idiot light) (by far the most common).
And Oil pressure sender (for oil gauge).
The switch (smaller part) does require a special socket to remove – but in some cases, you can use a normal deep socket (depending on how your socket wrenches are made).
The sender (larger all metal part) uses an end wrench to remove/install. I “think” it is 7/16” size. Generally the only cars I see with the oil pressure gauge are special order, police and taxis.
A huge majority of M-bodies came with idiot light (smaller switch).
To replace:
First, I would highly recommend taking car to a car wash and washing that area well before performing repairs – for that area might be pretty oily.
Disconnecting the air cleaner and moving it to the driver’s side helps to gain access.
Then just push the wires aside, disconnect the electrical connector, put the sorta special socket over it )(straight down) and unscrew like a (weird) bolt.
Reverse to install – but I would recommend threading the first few threads by hand.
It doesn’t need to be too terribly tight – just tight enough not to leak past the pipe threads. Too tight and it can break off.
If paying a shop to replace it, the tech would get paid about 0.7 (seven tenths) of an hour to replace the sending unit. I don’t think is a very difficult job. Many auto part stores might even have a socket to loan out.
The oil pressure switch does have a tendency to seep, to leak oil and even has been known to come apart – which means you have full engine oil pressure creating a geyser effect in rear of engine (which can drain the engine out of oil in no time).
Also, in that same area, the rear intake manifold gasket also has a tendency to leak oil – and that job is not fun. Not difficult per se, but lifting that 50 pound intake off and back on – does a number on your back.
BudW