76 duster gauges not working

There can be one or more of several issues.

"Changed the voltage limiter." Where did you get it and is it an original type? I would get a solid state one. RTE is one outfit

The gauge studs can be loose/ corroded and not make contact with the pc board. "Work" the nuts loose/ tight a few times

The contact fingers for the IVR may not make good contact with the PC board. Solder jumpers across the contact fingers to the PC board traces

The harness connector pins on the board may be loose/ corroded. Clean them up and solder them. Get your self some liquid or paste ELECTRICAL (electronic) soldering flux, NOT the stuff for plumbing, and some electrical solder
The PC board may not be grounding, which, originally, was through the cluster mounting screws. Find a common ground point on the board (follow grounding traces on instrument lamps to a mounting screw) and add a grounding pigtail, bolted to the column support or dash frame