Which port to use for coolant sensor?

[Bundy]

I have plenty of open ports on my 4bbl edelbrock mani but I am not sure which are vacuum and which lead to coolant. I would assume they all do because the vacuum one I am using is so high up.

What do you think?

 

[Viperwolf1]

Use the one in the first pic.

 

[ObscureMachine]

What viper said.

 

[76MaBronco]

Where can I get a neck like that in pic #2?? I'd love to get the temp sensor on my Explorer motor working...

 

[ryansbronco]

Where can I get a neck like that in pic #2?? I'd love to get the temp sensor on my Explorer motor working...

Four Seasons 84831

rock auto stocks them for less than $6
their pic dose not show the top view, but if you use Google images you'll have a top view for the above part number

 

[Broncobowsher]

#1 is the best option
#2 is after the thermostat, so it will read cold if the thermosat sticks shut. Will also stay cold until the thermostat opens then will suddenly jump up to operating temp. This port is designed for emissions control equipment so it will activate only after then engine is warmed up.
#3 will not read correctly. The general water path is out of the pump, through the block, up the back of the block into the head through the head to the front of the engine, out of the heads into the intake, through the thermostat housing and around the radiator. That port is located after the block and just as the water starts to enter the heads. The heads are the important part to keep cool and do the most heating of the water. You are measuring the water temp before the final heating. It will read too cold. This is a good choice for the factory to plumb in an EGR cooler. It isn't a "hot" water port, only a "warm" water port.