I have a multi gauge with fuel on the bottom and temperature on top.

The temp gauge does not move. Is this reading taken from the cht or oil switch?

I'm running carbs. A po removed all engine contents including wiring so I'm working from scratch.

The oil switch is new and works regarding the pressure light. The cht is as was on the engine when I bought it and unknown working order.

The oil temp reading comes from a sender in the taco plate, not all engines have a plate with a sender.

It's the oil temperature on the gauge.

The reading is taken from the sender at the front bottom of the case, can't remember if its right or left. There should be a green wire with a black stripe going out of the sender.

That wire normally goes to the center console.

You may just have to run some extra wire from the center console area to the dash gauge.

BTW the gauge has to match the sender to get good readings.

Make sure the sender and the gauge are a matched pair.

Plus there are different ranges you can get on the senders. I can't remember the details, but in Montana I had to change them out. They'd never move in the winter.

Thanks for the info.

I know where the temp sender should be now you describe it. What is the cht for? Fuel injection only?

Yes

The stock CHT also called ts2 in most manuals which is near cylinder no 3 is used by the FI to enrich the mixture when the engine is dead cold.

There are also aftermarket CHT sensors with gauges to monitor head temps. Usually that sensor is a ring that you put around a spark plug.