I have a 1974 F100 with the 460 and factory a/c. I am looking for a picture of how the heater hoses connect from the heater core to the engine? Does the hose on the right or left of the heater core (looking from under hood) attach to engine near thermostat and which one connects to water pump area?

Also, on mine each hose has a heater valve with vacuum hoses attached. Is this the stock setup? Each hose (inlet and outlet) having a vacuum valve on it? I haven't been able to find any pictures that show this? My hoses are red and I am not sure it this has been changed before and somehow rigged up different than stock. These were unhooked and ziptied up when I got the truck due to a heater core leak, with the heater core bypassed with a small loop right at the block.

Any help would be appreciated. I got the old core out and new core in and I am ready to hook the hoses back up. May spring for two new valves just because the old ones are rusty looking, but I would like to hook the old hoses back up to at least make sure the new core isn't leaking.

 

It doesn't really matter how the hoses are connected to the engine but from the factory the hose that goes to the water pump went to the heater nipple closest to the fender.
And someone has done a little "engineering" on the water valve. There should only be one and it is in the opposite hose, the one that goes to the thermostat area. I think someone did this because they don't know how Ford originally did it.
On the '73-mid '75 trucks with factory air the valve had two vacuum lines going to it. In mid-75 the design was changed to a valve with a single vacuum line. Sounds like they put two of the later valves in, why is another question.
The correct valve is D0DZ-18495-A
Dennis Carpenter Obsolete, Concord, NC has 6 (704) 786-8139
Green Sales, Cincinnati, OH has 4 (800) 543-4959
NOS Parts Source, Olathe, KS has 1 (913) 220-5746

Also, here is an illustration from the Ford parts catalog. It's for a 302/360/390 (they don't have one for the 460) but its the same basic setup.

 

Awesome. Thanks so much.


Now I need to figure out what is going on with the extra vacuum lines to the extra valve

It does look like there are some aftermarket vacuum line t's installed (the white plastic kind you get at the autoparts store). Maybe I can just trace them and eliminate those extra parts.

The vacuum line to one valve is black with a red stripe and the one to the other is black with a green stripe, then the second line to each valve is just a smaller black line. And it is actually two of the older, original style metal valves with two vacuum lines to each. The a/c was converted to 134a at some point (the is my late grandfather's truck), but that wouldn't have anything to do with the heater loop at all would it?

 

No, the R134a conversion wouldn't have any effect on the vacuum lines.
If both valves are working, I would ditch one of them.
At the firewall, behind the engine there should be a rubber grommet with three vacuum lines coming out of it. One big and two smaller ones. The big one should go to a small metal vacuum reservoir mounted on the driver's side splash pan, this is where the A/C pulls its vacuum from. The two smaller lines go to the water valve in the heater hose. I forget which goes where and I'm 1600 miles from my tech manuals so I can't look it up right now. I "think" the black w/ red stripe goes to the fitting on the end of the valve and the black w/ green goes to the other one.

 

I think you are correct. I dug into it after work today and realized that the red/black, green/black lines were just teed off of, so they were feeding both valves. I ran a new solid line from exit to pump and used the old one with valve to the fitting at the thermostat on the manifold. I wd-40'd the old valve and it is moving. Fired the truck up and let her warm up and, presto, I got heat. The blend door was working as well as it blew through all areas tried.

Weird thing though, after doing all this and starting the truck, it wouldn't idle. I had to hold the gas down a good bit to keep her running and when I let off it completely died. It isn't a vacuum issue that I know of, because this happened before I hooked that vacuum line back up to the manifold and had it closed off with a vacuum nipple plug. The only thing I can think of is when I unhooked my temp hose loop on the block, I lost some coolant out of the hose. It leaked down on the alternator and wire "rats nest" in that area. I then rinsed the area of with some water poured out of a bucket. I am wondering if maybe some moisture is messing with the electrical system and causing rough running?? I was getting 14+/- volts though when it was running? Any thoughts?