[Nick_R_23]

It depends on what type of fuel/ignition setup you will be running. For example, if you will be running EFI, either GM OEM or an aftermarket setup like Holley or Fitech, all of those will require use of the modern 2 pin sensor to operate, so you’d use the LS sensor like stock to operate the EFI. Then, you could either pull the temp output from the ECM to display on aftermarket gauges, or use a secondary stock sensor that matches the truck year to drive the original gauges.

I’ve heard that you can also use a 3 pin F body temp sensor that will work as a combo sensor. The black and yellow wires will be used for EFI, the green wire will drive a 1979 or newer stock gauge. I have not personally verified this will work but I have been told that it does.

In my case, I have a 1978 Chevy that will be getting a carburetor LS swap. I will be using the latest MSD ignition controller, which says it has an optional temp sensor input for more accurate timing. I haven’t opened it yet to verify, but I’m pretty confident that it uses a modern 2 pin temp sensor. I could attempt to use an F body temp sensor and make a jumper harness, or use the OEM LS sensor for the MSD box and use a stock 1979 sensor turned down in the passenger head, and use that to drive the stock dash gauge (with a change to a 1979 temp gauge to match the ohm sweep). Or, since the MSD box claims that the input is optional, just skip the use of a 2 pin sensor entirely and run a turned down 79+ sensor to drive the stock gauges in the drivers side head.