Is there a common ground somewhere that I didn't see? Battery is grounded to body and engine I do not remember seeing another. 83 sedan.. I have my fuel issue figured out now I don't have oil pressure voltage or temp gauges. I need some Ideas or point me in the right direction.

Is it possible the ground to the block is insufficient?

Rather than a ground issue, I think you have a power problem going to the cluster for those gauges. Get a voltmeter and check to see if those gauges are getting any voltage to them, using ground as your reference.

Well I found one wire that had unplugged so now I have a voltage gauge again. Still looking for the power source for the other two so I have something to trace back. I tried looking at the schematic in a Haynes but got my nowhere I can only kinda read wiring diagrams.. Cougar is right not a ground issue. I double checked. and used my trusty test light. Is there something that needs to be jumped with a weber swap when you had a interference carb? I didn't think so but I am really struggling here.. Trouble shooting makes me wish for explosives. ok only fr a few minutes at a time.

There should be a wire going to the gauges that also ties to a fuse and provides power to the gauges.

So it turns out my car picked this exact time to back out several screws on the back of the cluster so it was a ground issue but I would not have found it if I hadnt pulled the cluster..

Now for the IDK There is one plug with a black wire and one yellow with red stripe and I have no idea where it goes... OK you caught me I only mostly removed the cluster a friend did the unplugging, So what is it and what does it go to?

That plug reminds me of the one on the digidashes, its for the warning buzzer.

Dont think so on this one tho. I dont recall unplugging it, just the 2 round ones and the 3 main ones on the right.

So I say put it back together and go for it. If theres a serious issue, we'll fix it at the show.