Offroad Carburetor?

[crawlin68]

Ok all you carburetor guys, I need your help. Are there any 4 barrel carburetors on the market that perform good offroad? By offroad, I mean that preform good off camber and at steep angles. I've got my 79 351M engine that currently has the stock 2 barrel Motorcraft carb on it and performs fantastic offroad. But I want to improve the power of it with a new Edelbrock intake and 4 barrel, but don't want to run into runabilty issues while wheeling. I've done some reading on the Q-Jet and the Truck Avenger and they seem to have issues. Are there any other good options that you guys are running or have had good luck with?

I know, I know.......just go EFI, but I cannot find an EFI system that costs less than $2000 for the 351M. So that isn't an option at this time.

[71BRONCO71]

Re: Offroad Carburetor?

This is my theory on 4 barrel carbs. Trucks and cars are different

We use them off road and at higher elevations. We are not looking to dump a metric ton of fuel and air down the throat of the intake to make the wheels smoke while going 100mph. We are generally at idle, in a low gear.
How many CFM's is your current 2 barrel?

I know a lot of guys say that you will need to run a 650cfm carb for a V8. Why?
I ran a 470 cfm Holley TA with no problems. You have been with me patrick at bald Mountain which is roughly 10,000ft in elevation and my truck started up fine, idles perfectly and was never adjusted. I tuned that carb at 200ft in elevation and never once touched it.
All the people bitching about how "my Holley" or "My edelbrock" more than likely have something bigger than what the motor needs. (650, 750 or 850).

I switched to a FiTech to gain more reliability. It did the exact opposite. I regret selling my holley 470cfm TA.
The guy that has it now is running it on a lifted 1950's Chevy truck with a 383 motor and lives at 4000ft in elevation. He hasnt had one problem.

[curtsellers]

Re: Offroad Carburetor?

Anyone know what the stock Ford 2 bbl CFM is? I've been thinking of switching to a 4 bbl or EFI, but the current set up runs really well and reliable.

[71BRONCO71]

Re: Offroad Carburetor?

https://en.wikipedia.org/wiki/Autolite_2100_carburetor

[crawlin68]

Re: Offroad Carburetor?

From the research that I've done, the 2100 and 2150 carbs can have a flow rate from 190 CFM up 424 CFM depending on what size ventures your carb has.

Ryan, so you had good luck with your 470 CFM Truck Avenger carb offroad? Did it ever die or stutter on steep angles?

[71BRONCO71]

Re: Offroad Carburetor?

I was at the jamboree when the Rubicon caught fire. It was like driving on hwy 5 at 5pm in LA on a Friday before a three day weekend.
I didn't have any problems waiting in line to go up Cadillac hill.

Im about one more "hiccup" away from selling this fitech and buying a brand new 470 TA

[GREMLIN]

Re: Offroad Carburetor?

chevy tbi simple system. stock 350 should work for the 351. go to binder planet.com lots of info.

[PhantomEB]

Re: Offroad Carburetor?

I am fully convinced that I will not be running this Professional Products EFI systems due to no support.

More and more I am thinking a new carburetor would be the cheaper way to go. It’s not no daily driver or even a monthly driver, keep it simple and something to tinker with! Having my buddy over yesterday got me thinking old school tinkering adjusting the carb would get me back to my roots, especially now I got all the tools and knowledge with jet kits and all.

[RedBronco]

Re: Offroad Carburetor?

I have the bc broncos quadrajet stage 1 on my 302 and have had no issues off road. Been on the rubicon, out to moab and havent had to adjust for altitude. The only issue i had was the fuel bowl leaking into the intake through some plugs. Had to epoxy them closed and its been flawless since. Its a common problem with the Q jets.

My buddy runs a properly sized truck avenger on his 302 and i can run circles around him off camber. The q jet hasnt bogged, flooded no matter the angle. Even if i kill it at an odd angle the motor will start back up.

At one point i was thinking about going with EFI, but its hard to justify the cost and complexity with how happy i am with the carb.

I would call up BC and get one built to the right motor specs for your 351. I believe they are built by JET, and can be specd for different motors and situations.

[crawlin68]

Re: Offroad Carburetor?

This is my theory on 4 barrel carbs. Trucks and cars are different

We use them off road and at higher elevations. We are not looking to dump a metric ton of fuel and air down the throat of the intake to make the wheels smoke while going 100mph. We are generally at idle, in a low gear.
How many CFM's is your current 2 barrel?

I know a lot of guys say that you will need to run a 650cfm carb for a V8. Why?
I ran a 470 cfm Holley TA with no problems. You have been with me patrick at bald Mountain which is roughly 10,000ft in elevation and my truck started up fine, idles perfectly and was never adjusted. I tuned that carb at 200ft in elevation and never once touched it.
All the people bitching about how "my Holley" or "My edelbrock" more than likely have something bigger than what the motor needs. (650, 750 or 850).

I switched to a FiTech to gain more reliability. It did the exact opposite. I regret selling my holley 470cfm TA.
The guy that has it now is running it on a lifted 1950's Chevy truck with a 383 motor and lives at 4000ft in elevation. He hasnt had one problem.

Hey Ryan,

What size engine did you have your 470 Avenger?

[71BRONCO71]

Re: Offroad Carburetor?

I had a 470 on my 302 which isnt very beefy.

My old carb is sitting on top of a 383 small block at 4000ft

[DirtDonk]

Re: Offroad Carburetor?

Before you try to go with a 4bbl in place of your good running 2bbl, what else has been done to the engine? Unlike what I used to think, I would spend money on cam and exhaust before I would change the intake and carburetor for off-road.
For the street? Different opinion, but for keeping it simple (which changing a cam OR headers isn't really, I realize) try the other power adders first.

My own experiences have been that I like the way 4bbls work, but I never experienced a really large increase in power. Sure they ran good, and got the same fuel economy, but I would not say they ever lit me up with more power.
If you're running stock-ish exhaust, I'd do that first. Then add a cam.

Didn't you rebuild the engine a couple of years ago? Or has it been left stock?

Paul

[DirtDonk]

Re: Offroad Carburetor?

Is there a way to find out what size venturi it's got while still installed? In other words, can you wiggle yourself up on top of the engine with a flashlight to check the stampings! Unless they're right up front, it could be awkward to find.
But if the 351 got the larger 400+ cfm version, that would be even more reason to make sure the exhaust is good, in my opinion.

Paul

[crawlin68]

Re: Offroad Carburetor?

Is there a way to find out what size venturi it's got while still installed? In other words, can you wiggle yourself up on top of the engine with a flashlight to check the stampings! Unless they're right up front, it could be awkward to find.
But if the 351 got the larger 400+ cfm version, that would be even more reason to make sure the exhaust is good, in my opinion.

Paul

Hi Paul,

This is my plan as of now. If it does happen to be one of the large venture carbs, I'll probably just keep it. The engine is completely stock. I just took all of the smog equipment and miles and miles of vacuum lines and the A/C compressor off of it. I just bolted on a nice set of 1-5/8" mid length headers and will have dual 2-1/2" inch exhaust all the way out. So my thought was now that it's set up to evacuate more air, I should find a way to get more air in.