No chassis electrical

First post, so I apologize if this is wrong spot, or already answered. I have been 2 years into full body off resto of 87 v20 with T.B.I. 350. Everything that went back on was replaced with new or rebuilt. As many parts as available was AC Delco, everything else was researched for best option. Through this whole process I have found several answers to many problems or better ways to do things from this site, so thank all of you. My issue, that I tried to find a topic specfic to my biggest problem yet, is on the electrical side. Everything was finally ready to fire the engine for break-in, but when I trurned the key to on position volt, oil, and temp guages were obviously not working. I have all lights, turn signals, wipers, and 4WD indicator working, After going through here and a lot of googling most common solution was a ground. I have triple checked all grounds I am aware of, with no change in outcome. My next thought was fusible link, but I can’t find if there is more than one, or how to properly diagnos this. My cousin, who helped with the resto, is thinking ECM. I am really hoping someone has encountered something similar, or has a idea of where I should be looking.

Do you remember hooking up the instrument panel ground? Should be a black wire up under the dash, and on an ‘87 connected to a ground bus bar on the firewall up above your feet.

Also check to see the body is grounded to the engine (braided wire on the back passenger side of the engine) and the battery is grounded to the frame (wire from battery negative down to top of the frame near where a mechanical fuel pump would be).

I will check again, but quite certain cluster is grounded. I do have lights, blinkers, and indicators working properly. I know the firewall ground is good and secure, but I will also double check that. And completely certain of batt to core support to engine to frame are all good.

Another possibility, since you have power to lights, but apparently no ignition-switched power.
During your restoration, did you remove or drop the steering column? The ignition key turns a small toothed rack, which pulls a rod running up and down the column, and the actual switch is connected to the rod and mounted near the point where the column goes through the dash. That toothed rack is made of pot metal, and subject to breaking or cracking.

If the rack on the end of the key cylinder breaks, the rod is not pulled up and down correctly and it does not properly actuate the switch as you turn the key. Also, if the switch was unplugged or removed during your work, it may need to be readjusted up or down so the electrical contacts line up correctly.

The ignition column and switch is a standard GM design, and is used on many vehicles. Lots of online documentation for repairs.

Yes. The steering column was completely rebuilt as well. I will check on those ground points now that it is daylight.

I believe that I have verified good grounds. I took a volt meter and have 12V at various points on motor, frame, and body to B+. Not saying this is ruled out, but I also put the old ECM back in with no change in results. I can not trust that old ECM was good.

Check the connection for the bulkhead on the firewall. Mine looked tight but I put a socket on it and it was not.