I'm embarrassed to say that I can't find the oil pressure switch. Its a 1973 350. I found the wire, no switch in sight. I suspect someone may have replaced it with a plug at some point because it should be easy (I think). The service manual is no help either. Can anyone tell me exactly where to look?

 

Look between the water pump and intake, driver side. You should have a dark blue 16 gage wire running to that area.

Can't figure why anyone would have done away with it. Is there a copper or plastic tube for a pressure gage coming off the block at that location?

 

I'll have to look again for the tube you mentioned. There's a sending unit in the location you described, but I thought that was the temp sender. Can't trace it by the wire because they all screwed up. Trying to put everything back the way it should be.

 

Drew, the temperature sender is at the front of the intake manifold, to driver side of the top radiator hose and has a green wire. The oil sender will be on the "shelf", between the intake and water pump.

What service book do you have? the Oldsmobile factory CSM should have all that info and wiring diagrams in it.

 

I was just workine on those on my epic engine painting project.
A little blurry but you can see the sending units and the green and blue wires.