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390FE with autolight 4 barrel, what style choke is this?
Hey guys simple question here! Iv picked up a 72 F250 that is sporting a 390FE. Iv been more into the 302’s so im learning my way around the FE based motor and im really enjoyed it so far. My motor was a 2 barrel and the previous owner added a autolight 4 barrel and stock cast iron intake along with it. It has an auto choke but its not electronic or with coolant so it past my knowledge. It has a hard line coming off the choke that goes down to the passenger side exhaust manifold. It is not attached to the manifold and I don’t see any place for it to so my manifold may not support this system. I will try and include a photo!
That was easy! +1 to the forum!
its summer now and about 70-80° so cold starts are easy but it gets down to 20-30° here in the winter so I would like for it to work. My ultimate goal would be to use a manual choke I like to control the choke myself, jist a personal thing. If not is there a way to use the system in place? I have a holly 650DP but id like to stick with that I have. Also the plate under the carb has coolant running through it, is there a way to get rid of that or is it better to keep the preheat m?
Ok that choke from what I can tell uses 2 ways to make it open as the motor heats up.
First is that metal hard line. It should pass thru the exh. manifold and the line comes out the bottom and goes up to the carb where the hose with the cap is.
I should back up some as the cool air flow comes from the nipple on the carbs air horn down into the bottom of the exh. manifold. Heated air out the top to the manifold line to the choke to help heat and open it.
As you said your manifold may not support it the metal line to pass thru. A fix could be using copper, easy to bend, wrapped around the manifold and hooked to the metal line going to the choke and the other end to the carbs air horn like stock would be. May not be pretty but should work.
Also it looks like there is a bracket, half round thing by the black cap, that would hold a heater hose. The heater hose would get hot as the motor runs and being next to the choke cap it will also help heat the choke to make it open.
Now that heated spacer below the carb. It helps in cold weather driving mostly before the motor is up to full temp but can also keep the carb from icing up as it helps keep the carb warm.
During the summer you can "turn" the water off to it but come fall / winter / spring (cool damp days) I would turn it back on as that is when icing can happen.
As for manual or auto choke / swap out carbs it up to you. I have used manual chokes and I am getting lazy in my old age and if working right like the auto chokes.
Same with the carb, if it is working or only needs a little adjusting why change it.
My .02
BTW I have a 300 six in my 81 F100 and it used that same metal line to help heat the choke. Thing is I swapped on EIF exh manifolds and it does not have that line like yours. I plan on doing the copper line wrapped around 1 of the tubes to heat the air.
Also from the factory my cap uses a 6 volt connection from the ALT stator in place of the heater hose to help heat / open the choke. I guess you could find a cap from a newer carb (80-86) and run a wire from your ALY stator in place of the heater hose?
Dave ----
Hey guys simple question here! Iv picked up a 72 F250 that is sporting a 390FE. Iv been more into the 302’s so im learning my way around the FE based motor and im really enjoyed it so far. My motor was a 2 barrel and the previous owner added a autolight 4 barrel and stock cast iron intake along with it. It has an auto choke but its not electronic or with coolant so it past my knowledge. It has a hard line coming off the choke that goes down to the passenger side exhaust manifold. It is not attached to the manifold and I don’t see any place for it to so my manifold may not support this system. I will try and include a photo!
That was easy! +1 to the forum!
its summer now and about 70-80° so cold starts are easy but it gets down to 20-30° here in the winter so I would like for it to work. My ultimate goal would be to use a manual choke I like to control the choke myself, jist a personal thing. If not is there a way to use the system in place? I have a holly 650DP but id like to stick with that I have. Also the plate under the carb has coolant running through it, is there a way to get rid of that or is it better to keep the preheat m?
Thanks in advance!
I see two things wrong in that picture: your coolant line isn't up against the choke pull-off like it should be, and one of your choke pull-off heat risers is missing.
Yes unfortunately someone else has done the carb swap on the truck. Looke like a good thread to check out! Hope I can get this system running and not have to deal with a carb swap. Thanks for the info!!
Yes unfortunately someone else has done the carb swap on the truck. Looke like a good thread to check out! Hope I can get this system running and not have to deal with a carb swap. Thanks for the info!!
08-01-2018, 07:31 PM
