Which temp sensor feeds the temp guage?

[mckpaul]

Posted this in Engine & Drivetrain, but since this is where the 73-87 guru's are, thought I'd put it here too.....

I have an 84, it doesn't have an ECM, never did. When I got it, it had an 89 motor in it (305). It locked up. Bought a used 86 motor (305) from CRRoy71 here on the board to replace it with. Rebuilt it and now I'm in the process of putting it in.

Here's the deal. Never saw the original 84 305 motor. Both the 89 and 86 motors came from trucks that had an ECM, they have two temp sensors on them, one on the driver side head under the exhaust manifold, and one in the thermostat housing. I think one was to provide a signal to the temp gauge, and the other is for a engine temp signal to the ECM. Since I don't have an ECM, I only have one wire to feed the temp gauge, which is your basic stock gauge with 100 on the low end, 210 in the middle, and 260 on the high end. The wire is long enough to reach either place. I obviously need to plug one of the holes (they are both the same thread but one sensor has a round terminal, one has a spade terminal)

I'm pretty sure I need to use the sensor with the round terminal since that's the one that fits the connector on my wire. But was wondering if anyone had an 84 or earlier stock set up (with no ECM) that could tell me if the sensor should be in the head or in the thremostat housing. And am I on the right track with how it works? Just want to put it back the way it's suppose to be.