Hi all,

As the title states I have a 1975 Highboy F250 with a 1972 FE390 transplant. I am running into a little confusion with the vacuum lines coming from the carb - I'm not sure where any of them go...

The carb has a manual choke, which I swapped out to the original automatic choke (I have the original FE 360 carb). I have a line that comes out of the back of the choke and I need to know where that hooks into.

I also have a line coming from the firewall, which is not very long, but I have no clue where it hooks into. It looks as if it has a broken peice of white plastic the end, where it may have hooked into something on the original motor/vac lines.

I also have a line coming off the top of the front differential - where does that go and what does it do? Is it even a vac line?

If anyone has a 1972 and 1975 vac line diagram that would be most helpful, as I see no diagram on my truck anywhere. TIA

Mike

 

I'll try to help here as best as I can.

I am assuming that this is a 2bbl carb.
The line from the choke housing should go up to the bottom of the flat part behind the choke flap housing. It should have a barb hanging off of the bottom of it, so you will have a short (maybe 2") piece of hose there.

Are you sure that the hose from the firewall isn't for the windshield washers?
Does the truck have a/c? If not, it's probably the washer fluid hose.

The line on the front differential is a vent hose. It should just be run up high enough to keep water out of it. Maybe clamp it to the core support up out of the way.

Hopefully this will help.

 

'

Yes, sorry it is a 2bbl. Ok, the strange thing here is that the carb choke has a screw on "barb" that is probably almost 12 inches long - a semi flexible solid steel line. Seems strange if it only needs to go a couple of inches, but I'll take a look and maybe snap a picture or two to explain.

That line very well may go to the washers, but it has no resavior/pump right now. This hose is a bigger diameter than what hooks up to the sprayers and only seems to reach as far as the carb. Maybe this is a hookup that will turn off my "low fuel econ" light?

Awesome - that helps a ton. FWIW the old 360 carb seems to have a couple of hook up barbs that the 390 carb does not have. I also have a feeling that the 390 motor/carb came from a truck with an auto tranny because I think there is a kick down part attached to the throttle linkage. Could this be the case?

Thanks much!