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Carb jetting

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Eriksf250

Carb jetting

Good Evening everyone, random question for you all. For a stock 351ho, what should the jetting be on the carb? Has anyone put a 600 Edelbrock on a stock 351 and found out the correct jet size and needle size? I'm looking to get a carb from National Carburetors and I thought if I knew what it should have versus what it comes with stock, I might be able to have them set it up and get it really close for me. According to them, they said it comes with .098 primaries, .095 secondaries and 075x.047 metering rods. Any help is appreciated

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gary Lewis

Re: Carb jetting

Administrator

I don't know what jets the Holley would have had, but I ran a stock Edelbrock 1406 on a 351W and it ran fine. Stock they do have .098" primary jets, .075" x .047" needles, and yellow (4") springs.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Eriksf250

Re: Carb jetting

Thank you Gary for your help. Did you have to run a fuel pressure regulator? I have the over 8500 gvw fuel pump that has the return. I don't know if they put out too much fuel pressure stock.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gary Lewis

Re: Carb jetting

Administrator

I didn't have your setup so didn't have to run a regulator. But the Edelbrocks are a bit less tolerant of high pressure than the Holleys are. They don't like over 6 psi or their needles might leak and cause the fuel level in the carb to go high. I've never had that, but supposedly the issue mainly happens at idle since the fuel requirement is minimal, and the result is that the idle mix gets rich.

So you can try it and see what happens. If you have idle problems then add the regulator.

Gary, AKA "Gary fellow": Profile

FuzzFace2

Re: Carb jetting

You cant go by what someone else is running as they could be on top of a MT. and you below sea level.

Also unless you have a AFR gauge it will be a guessing game what you are running.

My 300 six runs great but with the AFR gauge I know it is running rich and can be leaned out just a bit.
I just been to lazy to do it

Dave ----

Dave G.
81 F100 flare side 300 six / AA OD / NP435 / 2.75 gear
http://cars.grantskingdom1.com/index.php/1980-Ford-F100?page=1
81 F100 style side 300 six/SROD parts truck -RIP
http://cars.grantskingdom1.com/index.php/1981-Ford-F100

Eriksf250

Re: Carb jetting

Happy Sunday to everyone and thank you all for your help. I ordered my 1406 Edelbrock from National Carburetors and it should be here Wednesday. I also ordered a tuning kit so I will be prepared to make adjustments if need be. I have an inline fuel pressure gauge that I need to install to see what kind of fuel pressure I'm pushing. It also looks like I have a factory wire for my electric choke too on my truck. Will it be sufficient to use for this carburetor? The ground side of the choke, would I just ground that to the base of the carb? I'm just trying to get this truck right now that it's now my daily driver and I want to squeeze as much mpg's out of it as I can. I currently think I'm around 5, 10-12 would be better and I wouldn't expect more than that with 4.10s.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gary Lewis

Re: Carb jetting

Administrator

The wire to the choke should be white with a black stripe, as shown in the schematic below from the 1986 EVTM. That wire comes from the choke relay, which is pulled in by the alternator. So as soon as the engine starts the relay should close and provide battery voltage to the choke, and that will work perfectly.

And taking the ground wire to the carb mounting bolt, or even a screw on the carb, will work fine.

Out of the box I think you'll be between 10 and 12 MPG, depending on how you drive. These trucks are not aerodynamic in any way, so anything about 65 MPH is causing serious drag. And with your 4.10s and no overdrive you'll be spinning the engine pretty rapidly, which doesn't help.

I ran a stock 1406 on my 460 at one point and it did well, so I'm sure you'll like yours.

Gary, AKA "Gary fellow": Profile

Gsmblue

Re: Carb jetting

I have a 1406 on my Bronco 351w. I am at about 4000ft altitude but I have the carb set as stock apart from the springs which I am cycling through at the moment. I am getting 10mpg.

1985.5 F-150 XL Explorer standard cab 5.0 EFI AOD 4x4
Daily Driver. We call her Eunice the Ute.

1982 Bronco XLT Lariat 351W AOD 4x4
Code name Esperanza, or Espy to her friends. Please see my Project thread for the blow by blow.

1984 F-350 XL Centurion crew cab 460 T19 4x4
"Eylza Dual-little"

Eriksf250

Re: Carb jetting

I'm at sea level so I'll see how it acts when I put it on and adjust if I have to. I found a carb adjustment chart with numbers that corresponds to what changes need to be done (needle, springs, jets) to achieve the best performance throughout the rpms. It will be my first time really diving into a carb and I'm excited to see how good I can dial it in.

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Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

LARIAT 85

Re: Carb jetting

In reply to this post by Eriksf250

Eriksf250 wrote

I'm just trying to get this truck right now that it's now my daily driver and I want to squeeze as much mpg's out of it as I can. I currently think I'm around 5, 10-12 would be better and I wouldn't expect more than that with 4.10s.

I am curious as to why you chose to get an Edelbrock over a stock replacement carburetor?

The Motorcraft 4180 carburetor your truck came with is the most precise carburetor Ford ever built, and is the same carburetor the mighty Mustang GT used from 1983 - 1985.

Lucille: 1985 Ford F150 XLT Lariat

*Colors: Dark Canyon Red exterior, Canyon Red interior
*Engine: 5.0, CompCams 31-230-3, "Thumper" E7 heads, Edelbrock Performer intake, Autolite 4100 carburetor, DuraSpark II ignition, Thorley Tri-Y headers, Flowmaster dual exhaust, H-pipe.
*Drivetrain: AOD transmission, 3.55 gears, 2wd.

Eriksf250

Re: Carb jetting

The 4180 was a Holley carburetor. I chose the Edelbrock because it's a little better on fuel mileage, no power valves to deal with, you can tune them pretty easy from what I've seen, and for a man who lives paycheck to paycheck taking care of his family, it cost less than the 4180 and 4160. Currently it has some cobbled together 670 truck avenger that a guy from work gave me. It's missing the fast idle setup for the choke so I can't use the choke. I have the mixture set rich enough to hold a cold idle. It stumbles and hesitates until it warms up and then it won't do it as bad. But this thing drinks worse than a 460 and is gutless for what it should be. I'm hoping when I get this edelbrock on and dialed in it should be a lot better. Right now, i think a 240 straight six would run circles around it.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gary Lewis

Re: Carb jetting

Administrator

You can get the 4106 dialed in. In fact, it may be so out of the box.

I won't get into the Holley vs Carterbrock wars since most people on here know my predilection. But I will say that I've seen the 1406 work well out of the box for 351's and 460's. And if adjustments need to be made they are pretty simple.

Having said that, I'd pull the top and invert it to check the float levels before I installed the carb. And I'd check the bowl to make sure there's no debris in it. So easy to do on the bench.
.

Gary, AKA "Gary fellow": Profile

Eriksf250

Re: Carb jetting

Update: Good afternoon everyone, so I just installed a fuel pressure gauge to check my fuel pressure and I'm getting about 4.5 psi. Does that seem ok and would it be ok for the edelbrock when I get ready to put that on?

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gsmblue

Re: Carb jetting

Yep. 3=6psi is the range I have read. 4.5 should be right in the sweet spot.

81-F150-Explorer

Re: Carb jetting

In reply to this post by Gary Lewis

Gary Lewis wrote

These trucks are not aerodynamic in any way, so anything about 65 MPH is causing serious drag.

What is ironic is Ford was very proud of their new aerodynamic design for the 80's.

Look at page 12 of the 1980 Brochure

1980 Brochure

and look at page 02 of the 1981 Brochure

1981 Brochure

And to paraphrase author, Douglas Adams:

"It glides through the air, in the same way that bricks Don't" - Douglas Adams

-----------------------------------------------

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.

351FUN

Re: Carb jetting

In reply to this post by Eriksf250

Yeah it'll like 4.5# it will not like 8, that I can tell you lol.

Eriksf250

Re: Carb jetting

I'm glad it should like 4.5 psi. I'm guessing the 3 port mechanical pumps on the over 8,500 gvw 351s have a high volume low pressure setup. I can't wait to see how it works tomorrow.

Erik 86 F-250 Heavy Duty, Standard Cab Long Bed, 2wd, 351HO, T18, Sterling 10.25, 4.10 open rear

Gary Lewis

Re: Carb jetting

Administrator

In reply to this post by 81-F150-Explorer

Yes, Ford seems to think they made big changes in drag coefficient over the previous years. But the big change came in '87 when they rounded the headlights and brought them out flush with the grille. Prior to that they were worse than the proverbial barn door as barn doors don't have recesses with which to hold onto the wind like our trucks do.

Gary, AKA "Gary fellow": Profile

BigBrother-84

Re: Carb jetting

Gary Lewis wrote

Prior to that they were worse than the proverbial barn door as barn doors don't have recesses with which to hold onto the wind like our trucks do.

Not sure the recesses have a noticeable impact on the general drag of our Barn Design Bullnoses.

But it didn't cost a lot for Ford to make this statement: Two nice colored lines above the truck gave the proof of its aerodynamical performances.

Isn't this an indisputable scientific evidence?

Jeff / 1984 F350 Crew Cab 4x4/5.8L w351 4V/ T18/ D50 4.10 front/ 8' bed.
Restored 2019-2022.
Nicknamed «Big Brother 1984», due to its soooo-looong shape & nod to George Orwell's 1984 famous novel.

81-F150-Explorer

Re: Carb jetting

I know our trucks were the first to be designed with aerodynamics in mind. And I do think they really tried.

You can see their attempt with the sloping fenders being taller at the windshield than at the front grille. (why I don't understand leveling kits to "correct" this. It's supposed to be lower in the front for aerodynamics than in the back.

)

The shape of the hood, grille and front bumper "\______/" being sloped to the sides.

And from the previous generation, 1973-1979 F-series, (which is also designed like a brick), I could see a 13% aerodynamic improvement over them. *

But with the newer generations of F-series, even the 1987-1991 / 1992-1996 and beyond, it makes our trucks look about as aerodynamic as a flat screen tv.

* 13% over the previous model isn't much is it.

I wonder what percentage the 1987-1991 got over ours? 50%?

Anyway ....

Truck: 1981 F-150 Explorer / Engine: 300-6 California MCU Feedback System / Trans: T-18 - 4 speed / 2.75 Ford Rear Axle Open Diff.