You'll be best to pull speedo, which gives you a hole to work through, then you can get at the tiny little fitting that seperates your oil pressure gauge from oil line. If you've still got the capillary tube temp gauge, you'll more than likely need to VERY CAREFULLY disconnect it from the block. There are a bunch of wires you'll have to work around....watch the old insulation, it cracks easy.
The key is to get enough room to pull the gauge cluster out far enough so you can get the back plate off and free up the Oil pressure gauge without doing too much collateral damage to the other stuff hooked to the cluster. I pop off the steering wheel for some additional room.
Personally, I'd rather drop the transmission than work on the gauge pack. That's one of the reasons why many (most) of us run a seperate oil, temp and ammeter pod!! BTW...that's a four beer job, but wait till you're finished to start sippin and make sure there aren't any kids within earshot. Hope this helps!!
