Need help finding new temperature gauge

Before you do that, make some tests. I keep trying to get guys to think of the instruments as AN END TO END SYSTEM.

There are many many things that can go wrong besides the gauges themselves. You MUST pull the panel out and simply go through each possible "point."

1--For temp, fuel (and oil if equipped) bad senders

2--For temp, fuel (and oil if equipped) bad wire connections at the senders

3--For temp (and oil if equipped) bad connections in the bulkhead connector

Bad connections at the harness connector at the cluster

Broken or loose connector pins on the instrument panel. You can repair these. On my 67, it was so bad I abandoned the original connector, soldered pigtails to the board, and bought "Molex" style connectors from Radio Shack

Bad contact fingers at the instrument regulator. On my 67 I had to solder jumpers from the contact fingers to the PC board traces

Bad or out of cal instrument limiter. I bought an aftermarket RTE, but I heard something the other day someone was having troubles contacting them. Who knows.

Bad nut connections at the gauge studs. Replace the "fake" nuts with real ones

Bad or out of cal gauges. Read onwards

Out of the gauges, through the PC traces, back out the connector pins, through the harness, bulkhead connector (except fuel) to the senders which can also be out of calibration

You can check gauge calibration several ways. One is to use a 1.5V dry cell, but I've forgotten. I prefer to check using the IVR, gauge, and a "dummy" sender of a resistor, with 12V battery just as it would be operating, installed in the cluster.

You can go to Radio Shack and buy resistors to test. All the gauges are the same movement.

For example, 1/2 scale is 23--35 ohms, so if you buy a pack of four 100 ohm, 1/2 watt resistors and wire all 4 in parallel, this makes one 25 ohm resistor. With 12--14V power to the IVR, and the 25 ohm resistor from the sender terminal of the gauge to ground, "about a minute" should result in a 1/2 scale reading on the gauge

Sender resistances are

L = 73.7 Ohms (empty)
M = 23.0 Ohms (1/2)
H = 10.2 Ohms (full)