As I'm putting this 5.9 Magnum in, it's time to put the oil pressure sending unit in, but mine has long hex volume that the sending switch screws into on the side, and there's also another tapped hole on the top for something, and I can't for the life of me figure out what is supposed to go on there. If anyone has any ideas, or if someone could snap a photo of theirs and tell me what is threaded in on top, I sure would appreciate it!

 

i am not 100% sure exactly what you are talking about but on my 81 there is the sensor for the gauge that goes in on about a 45* angle and then a oil pressure switch the screws into the side. the oil pressure switch is used if you have a oil pressure light and i think it is also use by the stock electric choke.

 

Thanks! That would make sense as to why I can't find what goes there, since I'm ditching the stock electric choke. It's in the corner of the garage, so I'll dig it out and confirm that is what is missing. If so, I'll just plug the other hole, or maybe the oil pressure sensor will thread into the hole that the hex volume is in.