Hoses for heater core

[gooberpat]

I'm trying to figure out where my heater hoses on my '65 Mustang go on my '87 XFlow I'm installing it into.
In the picture below I have 1, 2, and 3 as a possibility for one of the hoses. There is a fourth possibility beneath the
carburetor. I'm pretty sure one of the hoses connect to this fourth location. So that leaves the other hose to connect to
location 1, 2, or three.
If so, what are the other two locations used for?

 

[Frank]

#3 the water pump nipple must be used, best heat will be had from #2 or #1. #1 looks like the right size for heater hose. Using #3 with either #1 or #2 will give better heat than any fitting farther back in the head. Without #3 there will be no circulation, no heat.
If you're not using the emissions vacuum port it can be removed and plugged, as can the unused nipples in the rest of the head. If you're adding aftermarket temp gauge, where the vacuum port is is an excellent location for the temp sender.

 

[1981 Capri]

i cannot help with what goes where. but i go thru this on my other cars with V8 engines

Every pump has a vacuum side and a pressure side, so a common thing is the 3/4 larger size heater hose is the vacuum side of the water pump , and the smaller 5/8 size is the pressure side of the water pump .

My Fox Body does not have A / C , so in hot weather , to reduce heat in the cabin area , i installed a mini ball valve on the 5/8 - pressure side , to stop coolant flow to the heater core .

 

[DON]

Same here, I found a manual heater control valve. Generic. Come hot weather, I just flip it off, come cold weather, flip it on

 

[alwill923]

Should use a 3-way valve to keep the circulation correct.

 

[Cool23]

The connection below the carburetor would be a warmer some systems use. I have no heater in my Roadster but the system on that uses the heater hose system to flow water under the carburetor.

 

[DON]

Should use a 3-way valve to keep the circulation correct.

67 mustangs don’t use a 3 way. Non ac cars have no water valve and ac cars have a vacuum on/ off valve

 

[gooberpat]

I guess I was hoping someone actually had a car with an old XFlow in it so I would know what the stock configuration was.
Any chance of that or is this setup too old?