Hey guys I am thinking of converting from a 2bbl to a 4bbl carb on a 77 f-150 400. Is there anything i need to get besides the carb and a new intake? Also are there any suggestions? Thanks
David

 

depends on what you use you truck for offroading, normal everday use pulling, or street. And also do you want good gas mileage or bad.



Scott
LowCountry Swampers
Make or brake it Four Wheel drives

 

What 4 bbl intake fits on a 400M, A 351C intake ?
I've Never, ever seen a 4 bbl intake on a 400M

Dennis

78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles

 

Summit racing sells them. Edelbrock among others makes them. If you are thinking "factory", then you are correct, I don't think the Ford ever made a 4bbl 400.

 

[updated:LAST EDITED ON 18-Nov-01 AT 12:57 PM (EST)]>What 4 bbl intake fits on a 400M, A 351C intake ?
>I've Never, ever seen a 4 bbl intake on a 400M

A 351C manifold won't fit a 400 because of the taller block. Weiand makes a Stealth dual plane 4V intake and Edelbrock makes 2, the Performer 400 non-EGR and the Performer 400 EGR. All of them will fit either a 351M or 400. There are some spacers you can buy from Weiand that allow you to use whatever 351C manifold you want on a 351M/400. FoMoCo never offered the 351M/400 with a factory 4V.

 

I will be using it for street use. About the gas mileage i have heard that a 4bbl gets bad gas mileage and i have also heard that they don't because the second 2 barrels are only used when you hit the gas hard. I would like good gas mileage. Who wouldn't?
David


P.S How do i find out how many cfm i need?

 

>I will be using it for street use. About the gas mileage i
>have heard that a 4bbl gets bad gas mileage and i have also
>heard that they don't because the second 2 barrels are only
>used when you hit the gas hard. I would like good gas
>mileage. Who wouldn't?
>
>
>P.S How do i find out how many cfm i need?

I don't think you'll see much difference in gas mileage. You may even see a slight increase depending on how judicious you are with your right foot. Any 600-650 cfm carb will work fine. Even at 100% VE the 400 only uses 578 CFM at 5K RPM. A stock 400 won't pull much past that even with a 4V setup.

 

>Summit racing sells them. Edelbrock among others makes
>them. If you are thinking "factory", then you are correct,
>I don't think the Ford ever made a 4bbl 400.


I'm always thinking Factory Parts!
I didn't relaize what I wrote until I woke up this morning
"Of course ,after market parts are avaiable "
Duh Me !
I need more sleep and fish food.

Dennis

78 F-150 429CJ C6 ,Silver w/Explorer Pkge
641/2 Mustang,Pre-World's Fair Car #8092
64 Fairlane S/C waiting for a 390-4spd.
68-Mustang.Sunlit Gold 80,000 miles
Attachments:

 

I replaced the carb and intake on my 78 F250 with 400 with Holly Street Avenger 670 CFM 4v and Edelbrock Performer manifold. Even with the stock cam, I noticed an improvement on low end power. I had air to fuel ratio meter installed when I had the stock set up. It was running on the rich side when crusing, and with the new set up, it runs leaner while crusing, which means that it's actually giving me better gas milage over 2v carb.

 

Check out the tech articles. They have an article on how to choose your next carb. There is some great info on it.

Bob
1978 F-150 4x4

 

Find someone to do a first calss rebuild on your 2 barrel, you will not get $450.00 + improvements with a intake & 4 barrel.
IMHO of course.
http://www.clubfte.com/users/jowilker/USFlag.gif
John

jowilker email me
[link:www.ford-trucks.com/users/jowilker|My Club FTE Page] Member since 01 01

[link:www.ford-trucks.net/users/jowilker/NCFTE.html|NCFTO] North Carolina Ford Truck Owners Group

In the cool still quiet of night, you can hear chevies rusting away.

 

I have a 1972 with 302 in it and I put the Edlebrock preformance package in it, what a big difference.The milage is the same as long as I keep my foot out it. It is a 650 CFM carb.

 

 

>What 4 bbl intake fits on a 400M, A 351C intake ?
>I've Never, ever seen a 4 bbl intake on a 400M
>
>Dennis
>

Dennis, you need to get out more! :-)
Here's one intake that fits the 351M/400 (And the one I run):
A Holley "Street Dominator" P.N. 300-20 - no longer in production, but there are several still around.
In a healthy 400, it gives a huge increase in horsepower, with a correctly-jetted Holley carb of course, and a worthwhile increase in fuel economy.
I know, I know, it's a single-plane manifold and something like the Edelbrock dual-plane manifold *should* give better torque, fuel economy, etc. - but it emphatically DOES NOT. I can't say this too strongly: do NOT waste your time with an Edelbrock manifold on your 400!
If you do this, you could start with the Holley off an early-'80's 460, with slightly richer main jets to compensate for the lower air-flow in your 400.
Then make sure you've got the distributor from a '79 Bronco or F-series 351M or 400, and set it to about 10 degrees advance at idle; back this off a little if it cackles too much.
The final touch would be to use the cam from a '78 351M, which has much more overlap than the 400 cam. Make sure it's a '78 (or earlier): By '79, this cam had been ruined in Ford's futile search for a smooth idle.
This combo in my Bronco regularly gets 14.6 - 14.8 mpg on the Interstate, and runs 0 - 60 times around 12 seconds.
Other alternative manifolds would include just about anything your heart desires for a 351C, along with the Holley C-to-M adapter plates. Just don't expect it to be leak-free unless you are VERY careful!

 

I say go with an aftermarket intake such as a spreadbore edelbrock, coupled with a spreadbore Holley 600cfm carb. You'll get better mileage with a spread bore carb with manual secondaries(back 2 barrels). A spread bore's primarys are small, with larger secondaries. So as long as you stay off the gas, you'll be OK.