Would someone explain the purpose of the hot water connection just below the carb on my 68 360. Its a flat plate with an inlet and outlet connection. the carb bolts on top of it. I assume its some sort of a vapor lock prevention device that heats the air/ fuel mix.
I've had a few Fords over the years but I can't recall ever seeing one of these.

 

One of the reasons for that was to prevent carburetor icing.

 

No Kidding? Is it really needed today? I mean, years ago gas wasn't as clean as it is today and I guess carb icing might have been a problem but its unheard of now. In the summer a hot mixture would seem to hurt performance. I can remember back in the 60's when racers used to pack their manifolds with ice between runs to get a cooler denser fuel mixture. now that I think about it, I can also remember having to insulate fuel lines to keep them cool and prevent vapor lock. If thats all it does can I by pass it?

 

Sure you can by-pass it. Most engines didn't have it anyway. My 71 360 doesn't have it.

Carb icing and vapor lock are two different animals. I had a 60 I6 pu one time that had carb icing one time in cold weather and the carb was covered with a thin film of ice. It didn't quit, but it will stop an engine if goes long enough.

 

The only time you need it is on cold mornings of app 42 degrees or less and high humidity app 55% and higher. By the time the motor is at full operating temp like 5 or 6 minutes running engine heat plus the warm radiator air blowing over the motor will keep carb icing away. The intake exhaust crossover also helps. A thermal controlled heated air inlet snorkel will cure this besides allowing a leaner F/A ratio. If set up with a low inlet temp like app 72-74 degrees you will prevent carb icing, better cold weather drivability without the loss of air density and detonation problems.

 

^^^ lol, am i the only 1 that got a headache reading that?

 

The danger from carb icing isn't that it will quit, it is that the ice will build in the venturi and prevent the throttle from closing. You can probably bypass the heated spacer with heater hose and see if you notice any difference. If you are satisfied with the results you can remove the spacer later. (although aren't carb spacers kind of a thing now....??????)

 

It does help in very cold weather, but in moderate and especially in warm weather heating the air/fuel mixture is not good for performance.... The cooler the mixture, the better the performance.....

 

A carb spacer is required...just use one off a 1965/71 352/390 passenger car that doesn't have the heater hose connections.

Some of the cars carb spacer plates have a smog hose connection, just block it off using a rubber cap. That's what the parts catalog sez to do.

 

Thanks for the information. I pinched off the hoses and it ran just fine. Now I'm going to bypass this thing and while I'm at it, replace all of the heater hoses and the heater control valve..

Can anyone tell me the correct size? I know they are either 3/4 or 5/8 ID but I'd like to have them ready when I drain it.

 

5/8" heater hose, and the valve is:

C3UZ-18495-A .. Heater Water Valve-inline type (Motorcraft YG-133)

Still supplied by Ford = suggested retail price $33.62

Also available from NAPA, other parts stores.

The same valve was used 1963/72 on F100/350's and F500 and larger trucks from 1963 into the 1980's.