Working on a 64 Dodge 330. The temp gauge was all over the place, pegged at times, then now quits. Fuel gauge quit. Oil pressure still works. (reads high end of gauge) Gounded temp sending unit wire, with key on until gauge pegs. Pulled dash and built a solid state Voltage limiter, following internet directions. Tested with battery and volt meter, output is steady 4.97 volts on circut board to all three gauges. Installed dash, no fuel reading, temp doesnt read, oil pressure reads, but a bit lower than previously. Any ideas? Would like the temp gauge to work on dash, I installed a mechanical temp gauge to get real temp reading. Will replace tank sending unit.
I built a solid state limiter in my 64 Fury and all reads fine there...

so you still have a couple of checks.
are you getting voltage at the sending units?

did you check the gauges? 2 AA batteries in series to equal 3 volts should put them in the middle.

or you could try the grounding the line to the sending unit again and see if the gauge moves. don't wait till it pegs to cut the power.

Test each gauge to make sure it works.
Make sure the dash and voltage regulator have good grounds.
If you are using the standard LM7905 linear voltage regulator, It will need a heat sink to work correctly, otherwise it can only supply about 1/2-Amp of current before going into thermal shutdown, then all the gauges will read incorrectly low.
I think each gauge of a B-Body rally dash can pull around 1/4-amp (3/4+ Amp total) when registering on the high side (full fuel, high oil, hot temp.)
A 10-Ohm resistance load on each gauge should have the gauge reading near or at full-scale. 20-Ohm load the gauge should rear about the center of the scale. This is what I found for my 1969 rally dash, but I think is should be about the same for your car?

I have 4.96 volts at the temp sending unit. The dash gauge stumbles, then moves when grounding the wire. Doesn't peg the gauge.

Couldnt get the gas gauge to move, but did not bench test it while dash was out. It was moving previously, but not reading correct. I figured sending unit, this car sat for over 10 years.

Using a LM7905 linear voltage regulator, on a heat sink, built same thing for my car which works-although my fuel gauge only goes to 3/4 when full.

err, you used a 7805, right? The 7905 is a negative voltage regulator. You say you have 5v, so I'm assuming you have the 7805

Yes, +5v Fixed Voltage Regulator 7805.
Radio Shack #2062599
I have another set of gauges that work, checked with two "D" batteries, also ordered a fuel tank sending unit. Will pull the dash out again to change gauges next.

Your right, my bad, 7805 lol.
I bench tested my dash before installing it, and kept it powered for several hours with all the gauges reading full scale, while monitoring the regulator output voltage and current to make sure the regulator could handle the full load with out going into thermal shutdown.