Um, no , I still don't think you're grasping it. Let me try again. Every small block Ford water outlet/thermostat housing/upper radiator hose fitting or whatever you want to call it has (or is supposed to have) a barb on it for a small hose in addition to the large barb for the upper radiator hose. You can clearly see it here:



There is supposed to be a small hose with a 90 degree bend in it that attaches to that small barb on the water outlet and then also to the upper most barb on the water pump. It's called a bypass hose and its purpose is to allow water to circulate past the thermostat back to the water pump when the engine is cold and the thermostat is still closed. This allows the engine and coolant to warm up evenly and completely. The bypass hose looks like this:



and it attaches here:



Just go into any auto parts store and ask for a bypass hose for a 289 in a '66 Mustang and they should have it. You may have to trim it a little to fit as they are usually a little long so the same hose can be used for a 351W. Once you've got that ironed out, you can straighten out your heater hoses. There should be two threaded ports on your intake manifold right behind the thermostat like this:



Notice that the left one has a 90 degree elbow with a hose barb threaded into it. That's the supply port for the heater. The heater hose going to the LOWER bung on the heater core goes here. This is what the original 90 degree fitting in the supply port looks like:



Most auto parts stores (if you get ahold of someone who knows what they actually carry) should have one. The ones in the parts stores normally are brass and don't have the extension down into the manifold but they work just fine. The port just to the right of the heater supply port should have the temp sender in it just like that picture. I looked at your gallery pics and it looks like you've got the temp sender threaded into the heater supply port:



I can't tell for sure from your gallery pics (cuz of that big, gawd-awful Chubby distributor jammed in there ), but it almost looks like you don't have the second port on the right for the temp sender. I don't know why you wouldn't as every stock or aftermarket SBF intake should have at least two. If it doesn't, see if your intake has a coolant crossover at the rear of the intake with a plugged port and if it does, move the temp sender there instead. Once you've got the supply hose correctly fitted, you can finish with the return hose. The hose going to the UPPER bung on the heater core attaches to the second barb on the water pump right behind your alternator bracket that is slightly below and to the engine's right of the barb for the bypass hose. That ought to get things working and flowing the way they ought to. You'll probably notice that the engine temp warms up more steadily and quickly as well with the bypass hose in place. This is the only way to hook it up and have it working the way it's supposed to. If something here is still fuzzy, I can take a couple pics of the setup on the 289 in my Falcon this afternoon.

 

The heater hose nipple should go exactly where the diagram I posted shows it on the manifold. I don't recall 100% but it looks like the thing you are describing on the thermostat housing is were Joe says the bypass hose connects!

Those two drawings I posted above ARE the 289 intake manifold and heater hook up from the 66 Shop Manual I have.

 

Ok so I hook up the bypass hose off of the thermostat housing to the top hose fitting on the water pump, then I need to hook up the heater core hose to a spot on the intake where my water temp sensor is. I will have to find another place for the temp sensor unless I can find a small enuff fitting that will fit in the small opening right behind my temp sender.

 

Now I think you've got it! What model, brand, origin, etc. is your intake manifold?

 

Its summits knock off of a edlebrock intake. (Summit Racing SUM-226030 - Summit Racing Street & Strip® Stage 1 Intake Manifolds - Overview - SummitRacing.com) I have 3 openings on the front of the intake and the biggest one is where I put the temp sensor, did I put it in the wrong spot that was the only spot where it fit.

 

Your temp sensor should go to the smaller port that should be just behind or in your case under your distributor. You may need to get a different temp sensor to fit the hole. Or buy a brass adapter for it.

 

Ted's got it. The port in the manifold is sized for the stock Ford sending unit and your aftermarket unit is somewhat of a generic larger size. Adapters are the answer.

 

Sounds good guys, Ill switch everything around. Thanks for the help...

 

Kind of late to the party, but here's a pic...

 

ALBUQ F-1, thank you that helps alot...

 

Yeah but.....One picture is worth 1000 words!

And that one shows everything he needs to see!

 

Yep it shows the spot for the temp sensor in the drawing I posted in #10.

You may have an adaptor fitting on that sender unit that comes off to expose a smaller fitting that will fit in the smaller hole. Might be worth a look - fit fit!

 

Ok after I got all the hoses hooked up correctly I'm still having a problem. I started her up and let her warm up, it was at 180 for a few minutes then all of the sudden she shot way up to 210. I shut her off and heard the sound of water running out, when I got out and looked I seen the coolant was comming out of the overflow. I felt the hoses going to the heater core and they were cool, the upper radiator hose was cool and the by pass hose wasn't hot like the lower radiator hose so I'm wondering if maybe the thermostat os blocked or pinched or something like that.

 

Undoubtedly air locked. If you loosen the hose at the return side of the heater, with the engine cool, start it up and pull the hose clear of the nipple until all the air blows out, then shove the hose back on and tighhten the clamp. Obviously if you have a temp control valve it needs to be wide open.

 

You might also double check that the thermostat is installed the right way. If it's backwards, it will never open. The spring side goes towards the intake/engine. Like Ross mentioned, air in the system can cause weird stuff like this also. The small block Fords usually fill and burp easily. Did you fill it cold and then just cap it? If so, you could have some big air pockets. Fill the radiator cold and then start the engine with the radiator cap off. Leave it off while the engine warms up and add coolant as necessary. Put the cap on when the thermostat opens and it should be good. You'll know when the stat opens because the upper radiator hose will suddenly get hot and the coolant in the radiator will start circulating and steaming a bit.