[dataway]

Starting to test some of the gauges now. Hooked up the gas gauge to a good 12 vdc variable supply, set it around 12.2 and ran it through a resistor box I built. Reads full plus about 5% at 90.2 ohms (I tested at this point because most gauges read bit more than full when they are totally full). Zero ohms brings it down to empty right on the button.

Should I have tested at more like 13 vdc?

Think the gauge is good to go? The cluster itself is quite clean and in decent shape, been stored since the early 90's. Have a new PCB for it coming next week.

Tested the sender before installing, it was sending 0-95 ohms.

Any advice on attempting to test the idiot light senders? I don't suppose anyone makes senders for oil and temp that are different than the OEM specs. Would be nice to have a temp sender that triggers at 230 degrees, and an oil sender that triggers around 10 psi to give a bit more warning of impending issues.

[dataway]

Noticed that McMaster-Carr has adjustable set point pressure switches with 1/8 npt inlet, can get setup normal open or normal close, for about $30. Adjustable from 6-30 psi, a bit larger than normal but should fit. Seems like that would work well if the OEM sender is just an on/off switch. Once you knew what the normal idle pressure for your engine is the set point could be fine tuned.

[Andretti]

I don't think the fuel gauge readings will be much different at battery vs. charging system voltages. As for the warning light temperature sensors, I recall a long time ago making adjustments to one on a pontiac. See if there's an epoxy covered hole by the terminal, could be hiding a adjustment screw.

[dataway]

Just looked at the close up photos of one of the Rock Auto senders ... you can actually see an adjustment screw in a hole right next to the terminal.
Few minutes with a test rig, heat gun and IR thermometer gun and a person could probably set it for a specific temp.
Thanks.