Trying to find correct temp sensor

[ClaytonE]

I have a 1977 C10 with the original 77 C10 temp gauge. The truck has a mid 80s sbc350. From what I’m seeing online is that the mid 80s engine temp sensor is 3/8NPT thread and the original 77 350 was 1/2. What would be the correct sensor to use where I can get correct readings with the original gauge?

 

[Finkaire]

Either a 1/2” to 3/8” adapter or a 3/8” sensor. Easy piesy?

 

[Ricko1966]

The sensors don't have the same value year to year. You need to use the sensor that matches your year of gauge or find a sensor with those values. I've posted those values more than once. Use the search engine with me as the poster. I'll try looking also. Found it. See if there is a spot on the intake manifold to move your original sender to. It will read ~10° lower than head temperature but you will know what's going on.

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[75gmck25]

I would have to check my notes to verify, but think it is a TS-6 sending unit that a resistance profile that works well with my ‘75, and it has the 1/2” threads. The original GM sending unit is no longer available, so you need to find NOS to get the real GM version.

 

[ClaytonE]

Welp after more research there is no 3/8 NPT sensor that has the same resistance value as my 77 gauges. So I took matter into my own hands and got an original sensor and turned the 1/2 NPT sensor down on a lathe and turned it into 3/8 NPT. Works great .