proper carb for a 72 F-250 w/390, 4spd 2wd
#1
proper carb for a 72 F-250 w/390, 4spd 2wd
I am considering buying a 72 Ford F-250 2WD w/390, 4spd. It seems to run okay, but runs REAL RICH. Lopey idle, will stall if u dont feather the accelerator pedal, real black smoke out of the dual exhausts. Has headers and a 600 cfm 4 barrel holley on it now, owner says it's been rebuilt, I don't think so. Any suggestions as to which 4 barrel carb would work the best for mileage and performance? Thanks.
#2
Edlebrock seems to have a good economic and low maintenance carb. Check out Summit Auto Racing. If you're in Northern Nevada, I know there is a Summit Outlet in Sparks. The folks at Summit are pretty knowledgeable about which CFM, Jet Size, etc, and will set you up with the right stuff.
Welcome to FTE! And welcome to Nevada Chapter.
Welcome to FTE! And welcome to Nevada Chapter.
Last edited by olfordsnstone; 10-12-2006 at 12:18 AM.
#3
#4
#5
Best Carb for a 390
Originally Posted by oldfomoco
I am considering buying a 72 Ford F-250 2WD w/390, 4spd. It seems to run okay, but runs REAL RICH. Lopey idle, will stall if u dont feather the accelerator pedal, real black smoke out of the dual exhausts. Has headers and a 600 cfm 4 barrel holley on it now, owner says it's been rebuilt, I don't think so. Any suggestions as to which 4 barrel carb would work the best for mileage and performance? Thanks.
To learn the carburetors stock size jetting, you need its List Number which is on the primary side facing forward. take the air cleaner off and you will find it. You can go to the Holley web site and get all the stock sizes for your carburetor. The Holley, IMO, is by far the best carburetor for both performance and mileage. Problems like yours are common, and can be easily fixed.
***** B is absolutely correct. And the 600 CFM is perfect for the 390. Unless the 390 was a high rpm built up motor, it does not need more, and the smaller size is far better for low speeds, and you will have better flow through the smaller venturis.
I have used Carter AFBs before (which is what the Edelbrock is) and they are rather finicky and require tons of parts sets to get the jetting corect.(Edelbrock is very good about proper jetting on a special order) When you live at altitude, you are wanting to lean out the stock jetting and that is where the problem begins. They use "step rods" for power enrichment and final jet size. The step rods eventually wear the jet and cause enrichment. Any increase or decrease in jet size affects the power jetting, so increases or decreases must be done with both step rods and jets. You also have to remove the entire carburetor top to work on this. The Holley, in contrast, is far easier to work on, and unless the base and center part are warped, the thing will last forever.
Regards,
Alanco
Last edited by alanco; 11-01-2006 at 08:18 PM. Reason: addition
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